Is this a chemical or physical change and explain pls!!! I NEED HELP!!!!!!!!!!
Answers
Answer:
I think physical because it changes the actual tooth.
You got a cavity in a tooth: Physical
This process is a physical change because the chemical composition of the tooth structure remains the same, but its physical shape or structure is altered.
The gravy in the refrigerator turned jelly-like as it cooled: Physical
This is because the change in state of the gravy, from liquid to solid, is a physical change that does not alter the chemical composition of the gravy.
The sugar in the coffee dissolved: Physical
This is because the sugar molecules are not chemically altered during the process of dissolving in the coffee.
The red meat turned brown as it cooked: Chemical
This is because the heat from cooking causes a chemical reaction between the proteins and the oxygen in the air, resulting in a change in the chemical composition of the meat.
My room was white and I painted it a bright red color: Physical
This is because the paint and the wall remain chemically the same after painting, but only the physical appearance of the wall changes.
I sharpened my pencil before I started taking my test: Physical
This is because the process of sharpening only alters the physical shape of the pencil tip, but does not change the chemical composition of the pencil.
We made popsicles to bring to the picnic: Physical
The process of mixing the ingredients such as juice or fruit with sugar and water, and then pouring the mixture into popsicle molds, is a physical change because the chemical composition of the individual ingredients does not change.
Related Questions
In the table, give specific examples of ecosystem services coral reefs provide for other ecosystems. (3 points)
Provisioning
Supporting
Regulating
Cultural
Answers
Note that the specific examples of ecosystem services that coral reefs provide for other ecosystems are given in the attached table.
What are ecosystem services?Ecosystem services are the benefits humans derive from the natural environment, such as food, water, and clean air.
Ecosystem services are important because they provide essential resources for human well-being and support economic development.
Some example explained are:
Provisioning: Fisheries provide a source of food and income for many communities. Timber is a key resource for the construction and paper industries. Crop pollination is necessary for agriculture and food production.
Supporting: Soil formation provides the foundation for plant growth and food production. Nutrient cycling replenishes soil fertility and supports plant growth. Habitat provision supports biodiversity and the provision of other ecosystem services.
Regulating: Pollination is essential for plant reproduction and the production of crops. Water purification removes harmful contaminants from drinking water. Climate regulation helps to mitigate the impacts of climate change.
Cultural: Recreation provides opportunities for people to engage with nature and promotes physical and mental well-being. Aesthetic value refers to the beauty and cultural significance of natural landscapes. Spiritual and religious values are often associated with natural environments and provide cultural and social benefits.
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1. calculate the final concentration of sodium azide and dcmu in the locomotion chambers. show your work. The DCMU is a 10mM concentrationThe Sodium Azide is a 1M concentration.If you add 10mL of the Chlamydomonas, 100 microliters of sterile water, and 100 microliters of 10mM DCMU what is the final concentration of DCMU?If you add 10mL of the Chlamydomonas, 100 microliters of sterile water, and 100 microliters of 1M Sodium Azide what is the final concentration of DCMU?
Answers
The final concentration of DCMU in the locomotion chambers will be 0.1 mM. If 10mL of the Chlamydomonas, 100 microliters of sterile water, and 100 microliters of 10mM DCMU is added.
To Calculate the final concentration of Sodium Azide and DCMU in the locomotion chambers. The final concentration of Sodium Azide in the locomotion chambers will be 10mM (millimolar) if 10mL (milliliters) of the Chlamydomonas, 100 μL (microliters) of sterile water, and 100 μL of 1M (molar) Sodium Azide is added.
The final concentration of DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) in the locomotion chambers will be 0.1 mM (millimolar) if 10 mL (milliliters) of the Chlamydomonas, 100 μL (microliters) of sterile water, and 100 μL of 10 mM (millimolar) DCMU are added.
Calculating the final concentration of DCMU:
Formula: C1V1 = C2V2C1 = initial concentration of DCMU = 10 mMV1 = volume of DCMU added = 100 μL (microliters)C2 = final concentration of DCMU = ?V2 = final volume = 10 mL + 100 μL + 100 μL = 10.2 mL
(convert 100 μL to mL by dividing it by 1000)
Substituting the values in the formula:
C1V1 = C2V210 mM x 100 μL = C2 x 10.2 mL1000 (since 1 mL = 1000 μL)C2 = 0.098 mM (millimolar) = 0.1 mM (approx.)
Thus, the final concentration of DCMU in the locomotion chambers will be 0.1 mM if 10mL of the Chlamydomonas, 100 microliters of sterile water, and 100 microliters of 10mM DCMU is added.
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3. Assertion (A): There is a small gap left between the rails of a railway track
Reason (R): Cooling of substances result in contraction.
Both A and R are true but R is not the correct explanation of A
A is false but R is true
b.
c. A is true but R is false
d. Both A and R are true and R is the correct explanation of A
Answers
There is a small gap left between the rails of a railway track Reason (R): Cooling of substances result in contraction. Both A and R are true but R is not the correct explanation of A,
Why cooling causes contraction ?When a substance is cooled, it means that the heat is removed from the substance. This results in fewer excited molecules and, as a result, less random motion. The force of attraction increases, resulting in fewer spaces between molecules, which causes contraction.
Why there is appearance of gap between railway track?The gaps left between successive rails on a railway track as a result of the rails expanding in the summer. The gap exists to allow for this expansion. If no gap is left, the summer expansion will cause the rails to bend sideways. This will lead to train accidents.
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Balance and state the type for these equations: _Ca(OH)2 + _HCl —> _CaCl2+ _H2O
Answers
Answer:
1,2,1,2
Explanation:
The descriptions below explain two ways that water is used by plants on a sunny day.
I. In a process called transpiration, some liquid water in leaves changes to water vapor. The water vapor is released into the air through tiny pores in the leaves. This allows more liquid water from the soil to be pulled up the roots and stem to replace water lost from the leaves.
II. Plants use some of this water in leaves in a process called photosynthesis. During photosynthesis, water and carbon dioxide break apart and recombine to form two new substances, oxygen and glucose.
Based on the above description of transpiration and photosynthesis, which type of change happens to water during each process?
In transpiration, because some of its properties change, water undergoes a physical change but keeps its identity. In photosynthesis, because its identity changes, water undergoes a chemical change.
In transpiration, because some of its properties change, water undergoes a chemical change but keeps its identity. In photosynthesis, because its identity changes, water undergoes a physical change.
In transpiration, because its physical properties change, water undergoes a physical change and loses its identity. In photosynthesis, because it keeps its identity, water undergoes a chemical change.
In transpiration, because its chemical properties change, water undergoes a chemical change and loses its identity. In photosynthesis, because it keeps its identity, water undergoes a physical change.
Answers
The correct answer is: In transpiration, because some of its properties change, water undergoes a physical change but keeps its identity.
What are transpiration and photosynthesis?Transpiration and photosynthesis are both processes that involve the use of water by plants.
Transpiration is the process by which water evaporates from the leaves of a plant and is released into the atmosphere. This occurs through tiny openings on the surface of leaves called stomata. The water that is lost through transpiration is replaced by water absorbed by the roots of the plant from the soil.
Photosynthesis, on the other hand, is the process by which plants use water, along with carbon dioxide and sunlight, to produce oxygen and glucose. During photosynthesis, water is split into hydrogen and oxygen, and the oxygen is released into the atmosphere as a byproduct. The glucose that is produced is used as a source of energy by the plant.
In transpiration, because some of its properties change, water undergoes a physical change but keeps its identity. In photosynthesis, because its identity changes, water undergoes a chemical change.
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Answer:
Its A
Explanation:
Got it right on the quiz
Which are the factors that favor SN2 react a) Strong nucleophile, good leaving group, polar protic solver b) Strong nucleophile, good leaving group. c) Weak nucleophile, good leaving group, po d) Strong nucleophile, poor leaving group, po ors that favor SN2 reactions, as described during the lab lecture? aving group, polar protic solvent, methyl or primary halide. e, good leaving group, polar aprotic solvent, methyl or primary halide. o, good leaving group, polar aprotic solvent, methyl or primary halide. phile, poor leaving group, polar aprotic solvent, tertiary halide. uong nucleophile, good leaving group, polar aprotic solvent, tertiary halide. 4. Which alkyl halide reacts fastest with trimethylamine in SN2 reaction? a) CI
Answers
The factors that favor SN2 reactions are Strong nucleophile, good leaving group, polar aprotic solvent, methyl or primary halide.
SN2 reactions require a strong nucleophile, good leaving group, polar aprotic solvent, and a methyl or primary halide. The reason for this is that SN2 reactions occur in a single step, with the nucleophile attacking the substrate and the leaving group departing at the same time. When the nucleophile approaches the substrate, it must be in a good orientation to cause an SN2 reaction.The best orientation for SN2 reactions occurs when the substrate is methyl or primary, the solvent is polar aprotic, the nucleophile is strong, and the leaving group is good. When the leaving group departs, it must be able to do so quickly, so a good leaving group is required. Finally, the solvent must be polar aprotic, which means that it can stabilize negative charges while not inhibiting the reaction by solvating the substrate.
The nucleophile attacks the substrate from the rear in order for this reaction to continue. The angle of the nucleophile's approach to the supplied substrate with respect to the carbon-leaving group bond is 180o. Through a transition state, the carbon-nucleophile bond forms and the carbon-leaving group bond dissolves simultaneously.
The needed product is now created when the leaving group is forced out of the transition state on the other side of the carbon-nucleophile connection. It's crucial to remember that the product is created by inverting the tetrahedral geometry at the central atom.
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When preparing to light a gas burner, which of the following do you do first?
Answers
Answer: clear the area of anything flammable such as hair, chemicals, Ect.
Iron nail wrapped with copper wire Determine the standard reduction potential of the cathode half-reaction, the standard reduction potential of the anode half-reaction, and the standard potential of the cell. E°cathode ____
(V) E° anode ___ (V) E° cell ___ (V)
Answers
The standard reduction potential of the cathode half-reaction is -0.36V,
The standard reduction potential of the anode half-reaction is +0.34V,
and the standard potential of the cell is -0.02V.
The cathode half-reaction is the reduction of iron (Fe²⁺) to iron (Fe):
Fe²⁺ + 2e⁻ -> Fe; E°cathode = -0.36V.
The anode half-reaction is the oxidation of copper (Cu) to copper (Cu²⁺):
Cu -> Cu²⁺ + 2e⁻; E°anode = +0.34V.
The standard potential of the cell is determined by subtracting the standard reduction potential of the anode from the standard reduction potential of the cathode:
E°cell = E°cathode - E°anode
= -0.36V - (+0.34V)
= -0.02V.
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Dolostone is composed of the mineral dolomite, which is similar to calcite in limestone, except that dolomite contains_____
a. Iron
b. Aluminium
c. Silica
d. Magnesium
Answers
Dolostone is composed of the mineral dolomite, which is similar to calcite in limestone, except that dolomite contains magnesium.
Dolostone, also known as dolomite rock, is a sedimentary rock composed mainly of the mineral dolomite. Dolomite, a calcium magnesium carbonate mineral, is the primary component of dolostone, making up around 90-95 percent of the rock. Dolostone is a rock that is similar to limestone and is often mistaken for it.
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What is the purpose of the one balloon larger in size than the other balloons? o to represent unoccupied space in a molecule to represent any pair of electrons - bonding or lone pair to represent the space lone pairs occupy in a molecule Submit Request Answer
Answers
The balloon that is one size larger than the others serves to symbolise the area in a molecule inhabited by lone pairs of electrons, signifying unshared electron pairs in a particular region.
The Lewis structure is a chemical model that depicts how atoms and valence electrons are arranged in a molecule. The atoms are represented by symbols, and the valence electrons, which are the electrons at the highest energy level, are shown as dots or lines. In organic chemistry, the bigger balloon often designates a region of a molecule where electrons are not shared with any other atoms or groups. The structure and reactivity of the molecule are impacted by this region, which is referred to as a lone pair. The wider balloon makes it easier to see where these unshared electron pairs are located and how they affect the molecule's overall structure and behaviour.
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in this experiment, you will use universal indicator to qualitatively measure ph. the universal indicator in this experiment is a mixture of 4 common indicators allowing for a large ph range to be measured. the following table (also available in your lab manual) describes the individual components of our universal indicator. universal indicator components indicator low ph color transition ph range high ph color thymol blue (1st transition) red 1.2 - 2.8 yellow methyl red red 4.4 - 6.2 yellow bromothymol blue yellow 6.0 - 7.6 blue thymol blue (2nd transition) yellow 8.0 - 9.6 blue phenolphthalein colorless 8.3 - 10.0 fuchsia select all of the following statements that are true about the universal indicator. group of answer choices at ph 1.2, the indicator will appear red. the universal indicator is a single chemical compound. the universal indicator (or parts thereof) are in equilibrium and have an associated k value. at a ph 7, the indicator will appear colorless.
Answers
At PH 1.2, the indicator will appear red.
Universal indicator- The universal indicator is a mixture of 4 common indicators allowing for a large pH range to be measured.
At pH 7, the indicator will appear yellow due to bromothymol blue. The universal indicator (or parts thereof) are in equilibrium and have an associated K value.
K value- The K value indicates the amount of products and reactants present in the reaction. It is an equilibrium ratio of the concentration of products and the reactants.
A universal indicator is made by mixing bromomethyl, methyl orange and phenolpthalein in alcohol.
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salts are composed of both cations and anions, both of which can potentially affect ph. which of the following salts would you test if you wanted to observe how just anions affect ph? group of answer choices nach3coo cacl2 nahco3 tris-hcl na2co3 nh4cl
Answers
The salt which you would test if you wanted to observe how just anions affect pH is Na2CO3.
What is salt? Salts are inorganic compounds made up of a cation and an anion. Salts are formed by the neutralization of an acid with a base, for example, hydrochloric acid and sodium hydroxide form table salt: NaCl. The cation is typically a metal or a positively charged organic compound, whereas the anion is generally a non-metal or a negatively charged organic compound. The salt's properties are a function of the cation and anion and are hence unique.
Salt's effect on pH: Salts are made up of cations and anions, both of which can have an impact on pH. Cations and anions can both have an impact on the pH of the solution, but they can do it in different ways. The pH of a solution can be affected by the anion of the salt since it can act as a base or an acid. The pH of a solution can be affected by the cation of the salt since it can act as an acid or a base. For instance, if we dissolve copper sulfate in water, the pH of the solution will be acidic since the sulfate ion will be hydrolyzed to create sulfuric acid, H2SO4.
However, if we dissolve sodium carbonate in water, the pH of the solution will be basic because the carbonate ion acts as a base, picking up H+ ions from water molecules to generate HCO3- ions. Hence, Na2CO3 is the salt which you would test if you wanted to observe how just anions affect pH.
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Testing for Alcohols & Carboxylic Acids
1. The presence of a primary or secondary alcohol can be confirmed by reaction with acidified potassium
dichromate solution which changes colour from orange to green.
a) State the name formula of the reagent used to test for the presence of a primary/secondary alcohol.
b) State the colour change observed when this reagent reacts with an alcohol.
c) What type of compound is produced by the oxidation of a primary alcohol?
d) What type of compound is produced by the oxidation of a secondary alcohol?
e) Explain why the dichromate test does not work for tertiary alcohols such as methylpropan-2-ol.
Include the chemical structure of methylpropan-2-ol in your explanation.
2.a) Describe a simple chemical test for the presence of a carboxylic acid group in a molecule.
Reagent:
Observation:
b) Describe how you would confirm that the gas produced in this test is carbon dioxide.
c) Explain why, for a completely unknown compound, the hydrogencarbonate test is not conclusive proof
that a carboxylic acid group is present.
Answers
Answer:
a) Acidified potassium dichromate solution is used to test for the presence of a primary or secondary alcohol.
b) The orange color of the potassium dichromate solution is reduced to green when it reacts with an alcohol.
c) The oxidation of a primary alcohol produces a carboxylic acid.
d) The oxidation of a secondary alcohol produces a ketone.
e) The dichromate test does not work for tertiary alcohols because they cannot be further oxidized. Methylpropan-2-ol is a tertiary alcohol with the chemical structure:
CH3
|
CH3—C—OH
|
CH3
Since there are no hydrogen atoms attached to the carbon atom bearing the hydroxyl group, it cannot be oxidized.
a) A simple test for the presence of a carboxylic acid group is the addition of sodium hydrogencarbonate solution to the compound. The reagent reacts with the carboxylic acid to produce carbon dioxide gas.
Reagent: Sodium hydrogencarbonate solution
Observation: Effervescence (bubbling) due to the release of carbon dioxide gas.
b) To confirm that the gas produced in the hydrogencarbonate test is carbon dioxide, it can be tested with limewater. Carbon dioxide turns limewater milky/cloudy due to the formation of calcium carbonate.
c) The hydrogencarbonate test is not conclusive proof that a carboxylic acid group is present in a completely unknown compound because some other functional groups such as phenols and alcohols can also react with the reagent and produce carbon dioxide. Therefore, additional tests such as the dichromate test or Tollens' test may be needed to confirm the presence of a carboxylic acid group.
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Predict the product(s) obtained when benzoquinone is treated with excess butadiene:
Answers
When benzoquinone is treated with excess butadiene, the products obtained are 2,5-dimethylcyclohexadiene-1,4-dione and cyclohexene.
What is benzoquinone?Benzoquinone is also known as 1,4-benzoquinone or cyclohexa-2,5-diene-1,4-dione, is a colorless organic compound. The presence of two carbonyl groups in its structure provides it its characteristic quinone chemistry.
Butadiene, also known as 1,3-butadiene, is a conjugated diene. The reaction between benzoquinone and butadiene is called a Diels-Alder reaction.
The Diels-Alder reaction is a conjugate addition reaction that joins a diene and a dienophile to create a new six-membered ring. The most important characteristic of the Diels-Alder reaction is its stereospecificity. This reaction occurs between a cyclic diene and an alkene or alkyne dienophile.
The products obtained when benzoquinone is treated with excess butadiene are:2,5-dimethylcyclohexadiene-1,4-dioneCyclohexeneThe reaction proceeds with the dienophile (benzoquinone) being attacked by the diene (butadiene) in the Diels-Alder reaction to produce a cyclic adduct. The product is 2,5-dimethylcyclohexadiene-1,4-dione. Cyclohexene is formed as a byproduct of the reaction.
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A gas with a constant volume had an original pressure of 1150 torr and a temperature of 75.0 ℃. Pressure was decreased to 760 torr. What is the final temperature of the gas?a. -43.0 ℃b. 49.6 ℃c. 230 ℃d. -251 ℃
Answers
Answer:
A gas with a constant volume had an original pressure of 1150 torr and a temperature of 75.0 ℃. Pressure was decreased to 760 torr. What is the final temperature of the gas?a. -43.0 ℃b. 49.6 ℃c. 230 ℃d. -251 ℃
understand what are the effects when there is low [s], high [s], and when vo is one half of the vmax. biochem]
Answers
The effect of low [s] is that the rate of the reaction will decrease and the effect of high [s] is that the rate of the reaction will increase. When Vo is one-half of Vmax, the effect is that the reaction has reached its half-maximum velocity, or that the reaction has reached its maximum efficiency.
The rate of the reaction will decrease in the case of low [s] as the substrate concentration is too low to support the reaction. On the other hand, the rate of reaction will increase in the case of high [s] as there is a greater amount of substrate to drive the reaction.
To understand these effects in a better way, we can use the Michaelis-Menten equation to calculate the rate of reaction at various substrate concentrations (Vo and Vmax) and also the reaction's maximum velocity (Vmax):-
V = Vmax[S]/(Km + [S])
Where Vmax is the maximum velocity of the reaction, Km is the Michaelis constant, and [S] is the concentration of the substrate.
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isotopes are different forms of an element that have different ______.
Answers
Isotopes are different forms of an element that have different atomic masses. The number of protons in each atom of an element will remain the same, but isotopes of an element will have different numbers of neutrons, leading to different atomic masses.
Isotopes are different forms of an element that have different numbers of neutrons in their nuclei. The number of neutrons in an atom can vary from one to several, depending on the element. Isotopes are atoms of an element that differ in the number of neutrons present in their nucleus. The atomic number of an element is determined by the number of protons present in the nucleus. However, the isotopes of the same element differ in their mass numbers. The atomic mass of an element is determined by the number of protons and neutrons present in the nucleus.
The atomic number of an atom is the sum of the number of protons in the nucleus and the number of electrons in a neutral (non-ionized) atom. Each atomic number designates a particular element, but not an isotope; the number of neutrons in an atom of a given element can vary widely. Each isotope of an element has a particular mass number, which is determined by the number of nucleons (both protons and neutrons) in the nucleus. Therefore, the isotopes of an element have different atomic masses.
Isotopes can be radioactive or stable, depending on the number of neutrons present in the nucleus. For instance, carbon-14 is a radioactive isotope of carbon, while carbon-12 is a stable isotope.
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Select the correct molecule that is the main product of the Calvin cycle.
1. G3P
2. NADPH
3. Glucose
Answers
The molecule that is the main product of the Calvin cycle is glucose. The Calvin cycle is also known as the light-independent reactions.
It is a series of biochemical reactions that occur in the stroma of the chloroplast in photosynthetic organisms to produce glucose. The Calvin cycle is made up of three stages: Carbon fixation, Reduction and regeneration of ribulose bisphosphate. Here's a breakdown of each stage:
Carbon fixation: Carbon dioxide enters the Calvin cycle and is converted to organic molecules. During carbon fixation, Rubisco, which is a crucial enzyme in photosynthesis, catalyzes the reaction between carbon dioxide and ribulose bisphosphate, leading to the formation of a six-carbon molecule that splits into two three-carbon molecules. This three-carbon molecule is the starting material for the reduction process.
Reduction: The ATP and NADPH produced during the light-dependent reactions are used to convert the three-carbon molecule produced during carbon fixation into glyceraldehyde-3-phosphate. This process involves a series of biochemical reactions that require the use of energy from ATP and electrons from NADPH.
Regeneration of ribulose bisphosphate: Glyceraldehyde-3-phosphate, which is the main product of the Calvin cycle, is used to regenerate the starting material for carbon fixation, ribulose bisphosphate. During this stage, ATP is used to convert the remaining glyceraldehyde-3-phosphate molecules into ribulose bisphosphate. The Calvin cycle is an essential process in photosynthesis, as it produces glucose, which is the main source of energy for plants and other photosynthetic organisms.
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Which of the following properties increase as you move from left to right across a period? Select all that apply.
A)Ionization energy
B)None
C)Electronegativity
D)Atomic radius
Answers
Ionization energy and Electronegativity increase as you move from left to right across a period.
A period is a row in the periodic table of elements. It consists of elements with a similar number of atomic orbitals. The table is arranged so that elements with the same number of valence electrons are located in the same group, making it easy to identify the properties of elements.
Ionization energy is the energy required to remove an electron from a neutral atom in its gaseous state.
Electronegativity is the measure of an atom's ability to attract electrons to itself.
As we move from left to right across a period, the effective nuclear charge increases, thus both ionization energy and electronegativity increase.
Therefore, the correct options are A) Ionization energy and C) Electronegativity.
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jamal has a sample of a substance and was asked to determine the density of this substance. he measured the mass to be 20g and volume to be 5cm3. what is the density of the sample?
Answers
The density of the sample of a substance with a mass of 20 g and volume of 5 cm³ will be 4 g/cm³.
What is Density of substance?Density of a substance can be defined as the measure of the amount of mass which is contained in a unit of volume of that substance. The general trend is that most of the gases are less dense than that of liquids, which are in turn less dense than that of solids, but there are numerous exceptions also present in nature.
The density of a substance can be calculated with the help of the formula:
Density = mass/volume.
Given, Mass of substance = 20g
Volume of substance = 5cm³
Density of the sample = mass of substance/volume of substance = 20g/5cm³ = 4 g/cm³
Therefore, the density of the sample is 4 g/cm³.
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equal masses of two substances absorb the same amount of heat. the temperature of substance a increases twice as much as the temperature of substance b. which substance has the higher specific heat?
Answers
The substance with the higher specific heat is Substance B. Specific heat is the amount of energy required to raise the temperature of a unit mass of a substance by one degree Celsius.
What is the substance with higher specific heat?Since equal masses of two substances absorb the same amount of heat, the substance with the higher specific heat will require more energy to raise its temperature by one degree Celsius, meaning that it will experience a smaller increase in temperature when the same amount of heat is applied. In this case, since Substance A's temperature increased twice as much as Substance B's, Substance B has the higher specific heat.
When two substances have the same mass and absorb the same amount of heat energy, the substance with the lower specific heat will have a higher temperature increase. Therefore, if the temperature of substance A increases twice as much as the temperature of substance B, it means that the specific heat of substance A is lower than the specific heat of substance B.
The formula for specific heat is given as follows:
Q = mcΔT
where, Q is the amount of heat energy added or removed, m is the mass of the substance, c is the specific heat of the substanceΔT is the change in temperature.
Therefore, if Q and m are the same for both substances, then the ratio of their temperature changes is given by:
ΔTA/ΔTB = cB/cA
Since the temperature of substance A increased twice as much as substance B, it means that ΔTA = 2ΔTB. Therefore, we can substitute these values in the above formula and get:
2 = cB/cA⇒ cA = cB/2
Since the specific heat of substance A is half of the specific heat of substance B, it means that substance A has a lower specific heat as compared to substance B.
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how many years does it take for plastic to decompose
Answers
Answer: how many years does it take for plastic to decompose?
Well, it depends on the plastic, regular plastic can take up to 20 years to decompose, however, plastic bottles can take up to 450 years to decompose.
20pcm3 og a gas has a pressure of 510mmhg what will be the volume of the pressure is increased to 780mmhg, assuming there is no change in temperature
Answers
The volume of the gas will decrease from 20 cm³ to 13.08 cm³.
What is Boyle's law?Boyle's law is a gas law that states that the product of the pressure and volume of a gas is constant at constant temperature.
What is the significance of assuming no change in temperature in this problem?Assuming no change in temperature is significant because it allows us to apply Boyle's law to solve the problem. If the temperature were to change, we would need to use a different gas law, such as Charles's law or the combined gas law, to account for the change in temperature.
We can use Boyle's law to solve this problem, which states that the product of the pressure and volume of a gas is constant at constant temperature. Mathematically, we can express this as P₁V₁ = P₂V₂, where P₁ and V₁ are the initial pressure and volume, respectively, and P₂ and V₂ are the final pressure and volume, respectively.
Using this equation, we can solve for V₂:
P₁V₁ = P₂V₂
V₂ = (P₁V₁)/P₂
Substituting the given values, we get:
V₂ = (510 mmHg x 20 cm³) / 780 mmHg
V₂ = 13.08 cm³
Therefore, if the pressure is increased from 510 mmHg to 780 mmHg at constant temperature, the volume of the gas will decrease from 20 cm³ to 13.08 cm³.
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Density and molar mass of gases 0.96 g of a gas occupies a volume of 0.672L at STP (0°C and 1atm). What is the identity of the gas: O N2 or CO2?
Answers
The calculated molar mass of 32 g/mol is the same as the molar mass of oxygen. Thus, the gas is O2.
What is the identity of gas?Let us determine the molar mass of this gas. We can begin with the density of the gas as follows:
Density = mass/volume
Density = 0.96 g/0.672 L
Density = 1.43 g/L
We know that at STP (standard temperature and pressure), temperature is 0°C and pressure is 1 atm. We can use these values to determine the molar volume of a gas, which is 22.4 L.
Molar volume = 22.4 L at STP
Thus,
1 mole of gas occupies 22.4 L at STP
We can determine the number of moles of the gas as follows:
Number of moles = volume/molar volume
Number of moles = 0.672 L/22.4 L/mol
Number of moles = 0.03 mol
The molar mass can be determined using the following formula:
molar mass = mass/number of moles
molar mass = 0.96 g/0.03 mol
molar mass = 32 g/mol
The calculated molar mass of the gas is 32 g/mol. Now let us compare this molar mass with the molar mass of the given gases.
Oxygen (O2) has a molar mass of 32 g/mol
The calculated molar mass of 32 g/mol is the same as the molar mass of oxygen. Therefore, the identity of the gas is O2.
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write the empirical formula for at least four ionic compounds that could be formed from the following ions: o CIO3^-,
o nh4^ ,
o ch3co2^-,
o pb^4+
Answers
Empirical formulae are the ratios of atoms in a compound that show the lowest possible ratio of atoms per mole of compound.
What is the empirical formula?In this question, we are to find the empirical formulae for the following ions:
OCl³⁻, NH⁴⁺, CH₃CO₂⁻ and Pb⁴⁺
Empirical formula for OCl³⁻:Oxygen (O) forms an anion by gaining three electrons to form the oxide ion, O²⁻
The ClO₃⁻ ion has one O²⁻ and three Cl⁺ ions. Therefore, the empirical formula is OCl³⁻
Empirical formula for NH₄⁺ :Nitrogen (N) forms a cation by losing three electrons to form N₃⁺ while Hydrogen (H) forms a cation by losing an electron to form H⁺. Therefore, the empirical formula for NH₄⁺ is NH₄⁺
Empirical formula for CH₃CO₂⁻
The ion contains 2 Carbon atoms, 3 Oxygen atoms, and 4 Hydrogen atoms. Divide each number of atoms by the lowest number (2) to give the empirical formula: CH₃CO₂⁻
Empirical formula for Pb⁴⁺:Lead (Pb) forms a cation by losing four electrons to form Pb⁴⁺.Therefore, the empirical formula for Pb⁴⁺+ is Pb⁴⁺.
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What is the primary safety hazard associated with dichloromethane methylene chloride )?
Answers
The primary safety hazard associated with dichloromethane (methylene chloride) is its potential to cause serious health effects if it is inhaled or absorbed through the skin.
Dichloromethane is a colorless, volatile liquid with a sweet odor. It is commonly used as a solvent in various industrial and laboratory applications. Exposure to high concentrations of dichloromethane vapor can cause dizziness, headache, nausea, and even unconsciousness. Prolonged exposure can lead to more serious effects, including liver and kidney damage, as well as cancer. In addition, dichloromethane can be absorbed through the skin, and contact with the liquid can cause irritation or chemical burns. It can also react with other chemicals to form potentially explosive or toxic compounds. aTherefore, appropriate safety measures such as good ventilation, protective clothing, and gloves should be used when handling dichloromethane. It is also important to dispose of it properly and not to mix it with other chemicals unless under controlled conditions.
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an ammonium based buffer contain s0.175 m ammounium bromide and 0.0836 m acetic acid. what is the ph of this solution
Answers
The pH of a solution of ammonium-based buffer containing 0.175 M ammonium bromide and 0.0836 M acetic acid is 9.26.
What is the pH of this solution?
A buffer is a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid. It resists changes in pH when small amounts of acid or base are added to it.
For the buffer solution to work, its pH should be within the acid dissociation constant, Ka of the weak acid and the weak base, Kb. In this question, the buffer is made up of ammonium bromide and acetic acid. The Ka for the acetic acid, CH3COOH is 1.74 x 10-5. It is a weak acid. The buffer pH can be calculated using the Henderson Hassel-balch equation.
Henderson Hassel-balch equation pH = pKa + log ([A-] / [HA]) Where, A- is the conjugate base and HA is the weak acid, pKa is the negative logarithm of Ka, pKa = -log Ka = -log (1.74 x 10-5), pKa = 4.76. Ammonium bromide will act as a salt in this solution, and its conjugate base will be ammonia.
NH4Br → NH4+ + Br-NH4+ will combine with OH- to form ammonia, NH3 and water.NH4+ + OH- → NH3 + H2OIn this reaction, OH- will be added to the buffer.
To calculate the pH of the buffer, we need to know the concentration of NH4+ and NH3 at equilibrium. NH4+ will come from the ammonium bromide, and NH3 will come from the reaction above.The ammonium bromide dissociates as follows:
NH4Br → NH4+ + Br-
Therefore, [NH4+] = 0.175 M. The concentration of NH3 will depend on the OH- concentration, which will be used up in the reaction. We need to know the Kb of NH3 to calculate the concentration of NH3 at equilibrium.
Kb for NH3 is 1.8 x 10⁻⁵ NH3 + H2O ↔ NH4+ + OH
-Kb = [NH4+] [OH-] / [NH3]
Kb = [NH4+] [OH-] / [NH3]But [NH3] = [NH4+] as they are in equal amounts, so;
Kb = [OH-]
Kb = 1.8 x 10-5[OH-] = 1.8 x 10-5.
The pOH = - log (1.8 x 10-5) = 4.74.
The pH of the buffer = 14 - pOH = 9.26
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The coupling reaction of two radicals is ______________ and involves ______ arrow(s).
endothermic, one
exothermic, one
endothermic, two
exothermic, two
Answers
The coupling reaction of two radicals is b. exothermic and involves one arrow.
A radical is a chemical entity that contains an unpaired electron in its valence shell, which makes it highly reactive. Molecules that contain an unpaired electron are referred to as "free radicals." Coupling reactions between free radicals involve the interaction of two free radicals, both of which have an unpaired electron. A covalent bond is created when these two free radicals join together, effectively eliminating the unpaired electron. This coupling reaction can be exothermic or endothermic based on the number of arrows present.
For two radicals, only one arrow is needed for the exothermic coupling reaction. The reaction is exothermic, and heat is produced as a result of the reaction. The energy produced by the bond-forming reaction overcomes the energy of the starting materials. This energy that is generated raises the kinetic energy of the product's components. As a result, the temperature of the system increases. For two radicals, the endothermic coupling reaction requires two arrows. The reaction absorbs energy, causing the temperature of the system to decrease.
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because co2 combines chemically with water to form a weak acid called ______, water can hold perhaps 1,000 times more co2 than either nitrogen or oxygen at saturation
Answers
Answer:
Because CO2 combines chemically with water to form a weak acid called carbonic acid, water can hold perhaps 1,000 times more CO2 than either nitrogen or oxygen at saturation.
Explanation:
What is carbon dioxide (CO2)?
Carbon dioxide (CO2) is a colorless, odorless gas that occurs naturally in the Earth's atmosphere. Carbon dioxide is a waste gas produced by animals and humans during respiration and combustion. It is also produced by plants and algae during photosynthesis.
Carbon dioxide is an important greenhouse gas that contributes to climate change.CO2 can combine chemically with water to form a weak acid called carbonic acid. Because of this, water can hold perhaps 1,000 times more CO2 than either nitrogen or oxygen at saturation.
Carbonic acid can dissolve calcium carbonate, which is found in marine organisms' shells and is a vital component of coral reefs. As the acidity of the ocean increases as a result of increasing CO2 concentrations, this can have a significant impact on these organisms.
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If you wanted to shift the potential of the lead-zinc cell upward,toward 0.70 V, which of the following actions would give thedesired result? Check all that apply. *Ignore the currentchecks.
Anyaction that makes [Zn2+] smaller than[Pb2+].
Any action that makes [Zn2+]larger than [Pb2+].
Adding some concentratedZn(C2H3O2)2 solution tothe Zn2+/Zn couple.
Anyaction that makes Q > 1.0.
Addingsome concentratedPb(C2H3O2)2 solution tothe Pb2+/Pb couple.
Anyaction that makes log Q positive.
Any action that makes log Qnegative.
Any action that makes Q <1.0.
Answers
To shift the potential of the lead-zinc cell upward, toward 0.70 V, the following actions would give the desired result:
Add some concentrated Pb(C2H3O2)2 solution to the Pb2+/Pb couple
Adding some concentrated Zn(C2H3O2)2 solution to the Zn2+/Zn couple
Any action that makes [Zn2+] larger than [Pb2+]
A lead-zinc cell is a galvanic cell consisting of lead and zinc electrodes immersed in a suitable electrolyte. The potential of the lead-zinc cell is the difference in electrode potential between the lead and zinc electrodes, as determined by their concentration gradient.
Therefore, to shift the potential of the lead-zinc cell upward, toward 0.70 V, one should add some concentrated Pb(C2H3O2)2 solution to the Pb2+/Pb couple, add some concentrated Zn(C2H3O2)2 solution to the Zn2+/Zn couple, and any action that makes [Zn2+] larger than [Pb2+].
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