Which of the following measurements
have four significant figures? Select all
that apply.
1.001
120.0
Explanation:Significant figures are used in science to determine the precision of a number. Depending on the decimal point, sig figs are counted in different ways.
Decimal Points
When counting sig figs, you always start at the first non-zero number. However, sometimes you start from the left, other times the right.
If the decimal point is present, start counting sig figs from the left.If the decimal point is absent, start counting sig figs from the right.Remember to start counting at the first non-zero number.
For people in the Americas, there is a trick to remembering this.
If this decimal is Present, start from the Pacific. If it is Absent, start from the Atlantic.This works because the Pacific ocean is to the left of the Americas, and the Atlantic is to the right.
4 Significant Figures
The number 1.001, has 4 significant figures. Since there is a decimal point, we start counting from the left. The first digit is not zero, so we count all four places as significant.
The number 120.0 also has 4 sig figs. Like the number above, we start counting from the left because of the decimal. The first digit on the left is not zero, so we once again count all 4 digits as significant.
how do protons determine the identity of an atom
Explanation:
Proton is one of the subatomic particles which has a positive charge. The number of protons present will give the atomic number of the chemical element. Every element will have a unique atomic number. Thus, we can say that protons will determine the identity of an element.
A certain mass of nitrogen gas occupies a volume of 8.56 L at a pressure of 3.72 atm. At what pressure will the volume of this sample be 10.94 L
The final pressure of the nitrogen gas with the increase in volume is 2.91 atm.
What is Boyle's Law?Boyle’s law is a gas law that states that the pressure exerted by a gas (of a given mass, kept at a constant temperature) is inversely proportional to the volume occupied by it.
The relation can be given as:
[tex]P_1V_1=P_2V_2[/tex]
The initial pressure of the gas, [tex]P_1[/tex] = 3.72 atm
The initial volume of the gas, [tex]V_1[/tex] = 8.56L
The final volume of the gas, [tex]V_2[/tex] = 10.94 L
Substituting the values, the final pressure [tex]P_2[/tex] is given as:
3.72 × 8.56 = [tex]P_2[/tex] × 10.94
[tex]P_2 =\frac{3.72 * 8.56}{10.94} \\\\P_2 =2.91 atm[/tex]
Therefore, the final pressure of the nitrogen gas with the increase in volume is 2.91 atm.
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When testing the temperature of catalase, what would happen if you changed the temperature using the same tube with the same catalase and hydrogen oxide mixture?.
The substrate and enzyme would bind and react before all temperatures could be tested.
Before all temperatures could be tested, the enzyme would stop functioning after a short while.
What happens to the substrate and the enzyme?The enzyme and the substrate would bind and the reaction would breakdown hydrogen peroxide into hydrogen and oxygen. Once the majority of the substrate was consumed, the reaction would not proceed even if the enzyme was at the optimal temperature.
Specific substrate binding is a property of enzymes. For example, the enzyme catalase exclusively binds to hydrogen peroxide as a substrate.
The enzyme forms a complex with the substrate when it attaches to its active site, breaking down the substrate into products.
I understand the question you are looking for is this:
When testing the temperature of catalase, what would happen if you changed the temperature using the same tube with the same catalase and hydrogen oxide mixture?
The substrate would stop working after a few minutes before all temperatures could be tested.The enzyme would stop working after a few minutes before all temperatures could be tested.The substrate and enzyme would bind and react before all temperatures could be tested.Learn more about enzymes here:
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The solubility of pbso₄ in water at 25 °c is 7. 9 × 10⁻⁴ m. What is ksp for pbso₄?.
ksp = 2S²
= 2 [ 7.9* 10-⁴ moldm-³ ]²
= 124.82 * 10-⁸ mol² dm-⁶
The term Ksp denotes the solubility product. It is generally used to predict the precipitation of reactions. The Ksp of PbSO₄ is 6.24 × 10⁻⁷.
What is solubility product?The solubility product of a sparingly soluble salt is defined as the product of the molar concentrations of its ions in a saturated solution of it at a given temperature. By knowing the solubility product of a substance, it is possible to predict whether a substance precipitate out or not.
In short, the precipitation of an ionic substance from the solution occurs when the ionic product exceeds the value of its solubility product at that temperature.
Here PbSO₄ dissociates as:
PbSO₄ → Pb²⁺ (aq) + SO₄²⁻ (aq)
Ksp = [Pb²⁺] [SO₄²⁻ ]
= [7. 9 × 10⁻⁴] [7. 9 × 10⁻⁴]
= 6.24 × 10⁻⁷
Thus the value of Ksp is 6.24 × 10⁻⁷.
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? Question
The article mentions that the difference in the responses of men and women to the research study could be due to
confirmation bias. Use the Internet to look up "confirmation bias." Which of the following statements could support the
view that the difference is due to confirmation bias?
Select all the correct answers.
Many of the men may believe that they are fair and unbiased against women.
Many of the women may already believe that they face biases.
More men than women participated in the study.
The men who participated in the study were younger than the women.
Many of the men may believe that they are fair and unbiased against women.
Many of the women may already believe that they face biases.
What is confirmation bias ?
The propensity to seek for, understand, favor, and remember information that supports or confirms one's preexisting opinions or values is known as confirmation bias. People exhibit this bias when they choose facts that support their opinions while rejecting those that contradict them or when they interpret ambiguous facts as supporting their preexisting beliefs. Although confirmation bias cannot be completely avoided, it can be controlled, for instance, by critical thinking education and training.
Confirmation bias has been linked to poor decisions in the scientific, organizational, financial, and political spheres. These biases can preserve or reinforce views in the face of contradictory data and contribute to overconfidence in personal opinions.
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Answer:
Many of the men may believe that they are fair and unbiased against women.
Many of the women may already believe that they face biases.
Explanation:
How does the appearance of
the protist differ from that of the onion sample?
The appearance of the protist differ from that of the onion sample due to the presence of motile structures.
What is a Protist?This is an eukaryote which could be unicellular or multicellular and examples include protozoa etc.
The major difference between a protist and onion sample is that protists have motile structures such as flagella, cilia etc while plant cells such as onions don't have.
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By replacing hardware safety features with software controls in the therac-25 machine, aecl was able to?
Therac-25, AECL was able to reduce costs by replacing hardware safety features with software controls.
the Therac-25 was a laptop-controlled radiation therapy machine produced by Atomic energy state Canada limited in 1982 after the Therac-6 and Therac-20 units. It was involved in at least six accidents between 1985 and 1987, in which patients were given massive overdoses state radiation.
The Therac-25 machine was a state-of-the-art linear accelerator developed by using the company Atomic strength Canada restricted (AECL) and a French company CGR to provide radiation treatment to cancer sufferers. The Therac-25 become the most computerized and complicated radiation therapy device state its time.
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Life alters the atmosphere by producing and removing _____________________, carbon dioxide, and methane.
Life alters the atmosphere by producing and removing oxygen, carbon dioxide, and methane.
Burning fossil fuels like coal, and natural gas, including oil, solid waste, trees, and other biological materials release carbon dioxide into the atmosphere, along with some chemical reactions.
It is thought that the first billion years of Earth's history saw a lot of volcanic activity. With little to no oxygen, the early atmosphere was presumably primarily composed of carbon dioxide.
Therefore, life alters the atmosphere by producing and removing oxygen, carbon dioxide, and methane.
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Listed following are some distinguishing characteristics of comets, meteors, and asteroids. Match these to the appropriate category of objects.
The distinguishing characteristics of comets, meteors, and asteroids are its composition.
What are the characteristics of comets, meteors and asteroids?Asteroids are the fragments of rock that were left over from the creation of the solar system, Meteors are the rocks that enter the atmosphere of the Earth from space while on the other hand, Comets are the remnants of the formation of the solar system that are made of dust, rocks, and ice. All these materials i.e. comets, meteors and asteroids are different from one another due to its structure and chemical composition.
So we can conclude that the distinguishing characteristics of comets, meteors, and asteroids are its composition.
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state and appearance sodium chloride
Sodium chloride is white, crystalline solid at room temperature.
Sodium chlorideIt is a compound whose components atoms are sodium and chlorine.
The atoms of the two elements combine chemically through an ionic bond. The sodium donates it valence electron to the chlorine atom.
Thus, sodium chloride is an ionic compound. It has a characteristic white appearance and crystalline structure.
The compound is a solid at room temperature. It has a melting point of 801 °C.
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If you were presented with 2 liters of a 2m sucrose stock solution, how many grams of sugar would be in a 100ml aliquot?
Answer:
68.46 gms
Explanation:
2 molal solution means there is 2 moles of sucrose per kg of solvent (generally 1000 cc)
2 moles / 1000 ml * 100 ml = .2 moles
mole weight of sucrose = 342.3 gm/mole
342.3 gm/mole * .2 mole = 68.46 gms
Assume that helium behaves as an ideal gas. what is the estimated density of 1.0 g of helium gas at a temperature of 27 °c and a pressure of 3.0 atm? (note: use r = 0.0821 l∙atm∙mol−1∙k−1)
The density of the helium gas is 0.487 g/L
Calculation,
According to Ideal gas equation,
PV = nRT ...(I)
The values of some terms are given as,
P is the pressure = 3 atm
V is the volume = ?
T is the temperature = 27°C = 27°C + 273 = 300 K
R is the universal gas constant = 0.0821 L∙atm∙mol−1∙K−1
n is the number of moles of helium = given mass of helium/molar mass of helium
n is the number of moles of helium = 1 g/ 4 g/mole = 0.25 mole
So, by putting the value of all data given in the equation (i) we get,
3 atm × V = 0.25 mol ×0.0821 L∙atm∙mol−1∙K−1×300 K
V = 0.25 mol ×0.0821 L∙atm∙mol−1∙K−1×300 K/3 atm
V = 2.05 L
The formula of density = given mass /volume = 1g/2.05 L = 0.487 g/L
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Hat product forms at the anode during the electrolysis of molten nabr?
a. Na+ (l) Na(l).
b. Br–(l).
c. Br^3–(I).
d. Br^2(g).
Reaction at anode
2 Br- (aq) -----> Br2 (g) + 2e-
The product formed at the anode is Br2 (g).
In chemistry and production, electrolysis is a technique that makes use of direct electric present-day (DC) to power an otherwise non-spontaneous chemical response.
Electrolysis is commercially crucial as a degree inside the separation of factors from clearly going on sources including ores the usage of an electrolytic cell.
The voltage that is wanted for electrolysis to occur is called the decomposition capacity. The word "lysis" way to split or break, so in phrases, electrolysis would imply "breakdown via power".
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Two trains, A and B are moving at a speed of 20 km per hour
and 30 km per hour respectively. Which type of energy do
these two trains have?
Answer:
[tex]\fbox {kinetic motion}[/tex]
Explanation:
As the trains are clearly in motion, we can understand the these trains possess kinetic energy, which is by virtue of a motion of a body.
Answer:
type of energy that two train have are kinetic energy
Calcium (Ca) and diatomic oxygen (O2) combine to form calcium oxide (CaO). The data table below compares the properties of these substances.
Calcium (Ca) Oxygen (O2) Calcium Oxide (CaO)
Melting Point (°C) 842 −218.4 2613
Density (g/cm3) 1.54 0.00143 3.34
Appearance silvery-white
metal colorless,
odorless gas white, odorless
powder
What can be concluded from this data?
A.
A chemical reaction occurred because calcium oxide has different properties than calcium and diatomic oxygen.
B.
A chemical reaction did not occur because solid calcium cannot chemically react with diatomic oxygen gas.
C.
A chemical reaction did occur because calcium oxide has similar properties to calcium and diatomic oxygen.
D.
A chemical reaction did not occur because calcium oxide is not a new substance.
A chemical reaction occurred because calcium oxide has different properties than calcium and diatomic oxygen. The correct option is A.
What are chemical reactions?A chemical reaction is said to occur when the chemical properties of substances change during the course of the reaction.
From the illustration, the chemical properties of calcium oxide are unique from that of calcium and oxygen. Thus, calcium oxide has become a new substance entirely.
Once a reaction leads to the formation of new substances, such a reaction is a chemical reaction.
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Please help me!!!!!!!!!!!!!
1)The limiting reactant will be aluminum acetate
2) The mass of aluminum hydroxide formed will be 9.75 grams.
Stoichiometric problemThe equation of the reaction is as below:
[tex]Al(C_2H_3O_2)_3 + 3NaOH --- > 3C_2H_3NaO_2 + Al(OH)_3[/tex]
The mole ratio of the 2 reactants is 1:3.
Mole of 100 mL. 1.25 mol/L [tex]Al(C_2H_3O_2)_3[/tex] = 0.1 x 1.25 = 0.125 mol
Mole of 300 mL, 2.30 mol/L NaOH = 0.3 x 2.3 = 0.69 mol
Thus, aluminum acetate is limited.
Mole ratio of [tex]Al(C_2H_3O_2)_3[/tex] and [tex]Al(OH)_3[/tex] = 1:1
Equivalent mole of [tex]Al(OH)_3[/tex] = 0.125 mol
Mass of 0.125 mole [tex]Al(OH)_3[/tex] = 0.125 x 78 = 9.75 grams.
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Which answer best describes what is happening in the following reaction?
2C8H18 + 25O2 Right arrow. 16CO2 + 18H2O
This is not a redox reaction. It is an example of combustion.
This is a redox reaction in which octane (C8H18) is the reducing agent.
This is a redox reaction in which carbon dioxide (CO2) burns due to ignition.
This is not a redox reaction, because a solution of carbon dioxide and water results.
A. This is not a redox reaction. It is an example of combustion.
Combustion reaction of hydrocarbonDuring the combustion of a hydrocarbon, the hydrocarbon reacts with oxygen to create carbon dioxide, water, and heat.
Example of combustion reaction2C8H18 + 25O2 → 16CO2 + 18H2O
Thus, we can conclude that, this is not a redox reaction. It is an example of combustion.
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Answer:
A: This is not a redox reaction. It is an example of combustion.
Explanation:
Consider the following equation in chemical equilibrium. C2H4(g) H2(g) C2H6(g) 137 kJ What happens to the amount of ethane (C2H6) when the temperature of the system is increased
The amount of ethane decreases
increasing the temperature (adding energy), will drive the reaction to the left
What happens to the amount of ethane (C2H6) when the temperature of the system is increased ?C2H4(g) <--> C2H6(g) + 137 kJ
because this reaction is an exothermic reaction and the heat is a product of this reaction, So when the number of temperature increases
so (more heat will be added) so the reaction will go leftward (toward reactants ) so the amount of C2H4 & H2 will increase and the amount of ethane C2H6 will decrease.Learn more about Chemical Equilibrium here:
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EXPERIMENT 1: How do you expect your coarse titration volume at the color change to compare to your fine titration volumes?
In the endpoint when the indicator changes color it gives the information that the acid is neutralized by the base.
What is Titration ?Titration is also known as titrimetry is a technique where a solution of known concentration is used to calculate the concentration of the unknown solution. Titration is a laboratory technique.
What is Endpoint ?The point at which the indicator changes the color is known as Endpoint.
Thus from the above conclusion we can say that In the endpoint when the indicator changes color it gives the information that the acid is neutralized by the base.
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Vinegar contains carbon, hydrogen, and oxygen with percent masses of 40.01% C, 6.70% H, and 53.29% O, respectively. Determine the empirical and molecular formulas of the compound. The molar mass of vinegar is about 60 g/mol. HOW DO WE GET THERE
The empirical formula is = C2H4O2
Molecular formula=C2H4O2
Calculation of Molecular formula and empirical formula:-Vinegar has three elements:
oxygen = 53.29%,
hydrogen = 6.70%,
and carbon = 40.01%.
We can create an equation for the total mass of vinegar with 'a' carbon atom,' b' hydrogen atom, and 'c' oxygen atoms using the molar masses of C, H, and O.
12*a + 1*b + 16*c = 60
We also know that C makes up 24 g/mol, or 40.01 percent, of the overall mass of 60 g/mol.
The formula contains two C atoms because each C atom has a molecular mass of 12 g/mol. You may determine that the formula contains 4 H and 2 O atoms by using the same reasoning for H and O.
The empirical formula is = C2H4O2
Molecular formula= (C2H4O2)n
(4 x 12 + 1 x 4 + 16 x 2)n = 60
(84)n = 60
n=60/84
n=0.71=1
Molecular formula=C2H4O2
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A molecule that contains delocalized electrons ________
Answer:
benzene molecule
Explanation:
The molecules exhibiting delocalization of electrons will have at least two resonance structures. These two resonance structure are having the equal energy.
What is resonance?Resonance is an electronic property of molecules by which, the sigma bond or pi bond moves from one location to other forming different mesomeric structures of the compound.
For example carbon dioxide can have two resonance structures.The lone pair in oxygen delocalize from one oxygen to the other. The double bond with carbon can be of either side of carbon. Thus one negative charge forms for one oxygen. This charge can be on the second hydrogen too.
In this way free electrons can delocalise through the orbitals and this process make the molecule more stable. The resonance structures together form the canonical structure which is the most probable and stable form of the compound.
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Help, Kinda struggling here
The water cycle will be discussed here.
What is Water cycle?
This is defined as the continuous manner in which water is moved within the earth and the atmosphere.'
The water cycle comprises of steps such as:
EvaporationCondensationPrecipitationHumans however disrupt water cycle through the damming of rivers and deforestation.
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What happens to iron in a bolt as the bolt rusts?
Answer:
write the following as fractions in their simplest form
About how long does it take for the reaction to reach equilibrium in this concentration versus time graph?
a graph of reactant and product concentration vs. time; a red curve shows the reactant concentration decreasing while two blue curves show the product concentration increasing with time; both blue curves intersect the red curve; the chemical equation is water reacting to produce hydrogen and oxygen
A.
0.5 second
B.
1.5 seconds
C.
2.5 seconds
D.
4.5 seconds
The time taken for the reaction to reach equilibrium in this concentration versus time graph is 4.5 seconds and is denoted as option D.
What is Time?This refers to the duration in which a certain action or activity takes place with its unit being seconds.
From the graph we can deduce that:
The two blue lines, the concentrations of H₂ and O₂, become flat between 4 and 5 seconds.The red line, the concentration of H₂O, becomes flat, also, between 4 and 5 seconds.This therefore means that the time taken for the reaction to reach equilibrium in this concentration versus time graph is 4.5 seconds.
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Answer: 4.5 is right just took the test.
Explanation:
a group of atoms of more than one elements forms
Considering the definition of chemical compounds, a group of atoms of more than one elements forms chemical compounds.
What is a chemical compoundChemical Compounds are substances that are made up of a minimum of 2 elements that have reacted with each other to give another substance different from the initial elements. Elements are held together by what is known as a chemical bond.
In other words, a chemical compound is any substance formed by the union of two or more types of chemical elements, that is, by atoms of two or more different types of chemical elements, joined together by chemical bonds in certain proportions.
A chemical compound can be separated into its constituent elements by chemical reactions.
SummaryIn summary, a group of atoms of more than one elements forms chemical compounds.
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A diprotic acid is titrated with a strong base. The pH at the first half-equivalence point is 3.27. The pH at the second half-equivalence point is 8.53. What is the value of ka2
A diprotic acid is titrated with a strong base. The pH at the first half-equivalence point is 3.27. The pH at the second half-equivalence point is 8.53. The value of ka2 is 27.89.
What is pH ?pH is used to measure whether the substance is acidic, basic or neutral and the range is 0-14. If the pH is less than 7 then the solution is acidic in nature. if the pH is more than 7 then the solution is basic in solution. If the pH is equal to 7 then the solution is neutral in nature.
How to find the polyprotic value ?To find the polyprotic value
[tex]K_{a_2}[/tex] = pH of first half equivalence point × pH of second half equivalence point
[tex]K_{a_2}[/tex] = 3.27 × 8.53
= 27.89
Thus from the above conclusion we can say that A diprotic acid is titrated with a strong base. The pH at the first half-equivalence point is 3.27. The pH at the second half-equivalence point is 8.53. The value of ka2 is 27.89.
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Which answer best describes what is happening in the following reaction?
2C8H18 + 25O2 Right arrow. 16CO2 + 18H2O
This is not a redox reaction. It is an example of combustion.
This is a redox reaction in which octane (C8H18) is the reducing agent.
This is a redox reaction in which carbon dioxide (CO2) burns due to ignition.
This is not a redox reaction, because a solution of carbon dioxide and water results.
The statement that best describes what is happening in the following reaction is this is not a redox reaction, It is an example of combustion (option A).
What is a combustion reaction?A combustion reaction is a reaction wherein a substance is combined with oxygen, usually at high temperature, releasing heat.
According to this question, octane undergoes a combustion reaction to produce carbon dioxide and water as follows: 2C8H18 + 25O2 = 16CO2 + 18H2O
Therefore, the statement that best describes what is happening in the following reaction is this is not a redox reaction, It is an example of combustion.
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Answer:
A: This is not a redox reaction. It is an example of combustion.
Explanation:
A student started with 0.3295 g of copper. The mass of filter paper and copper (II) oxide product was found to be 0.5723 g, and that of the filter paper alone was 0.2568 g. Calculate the percent yield of copper (II) oxide.
The percent yield will be 95.75%
Percent yieldMass of copper = 0.3295 g
Mass of filter paper + copper (II) oxide = 0.5723
Mass of filter paper only = 0.2568
Mass of copper (II) oxide = 0.5723 - 0.2568 = 0.3155
Percent yield = yield/total x 100%
= 0.3155/0.3295 x 100% = 95.75%
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The following reversible reaction is at equilibrium. If the concentration of HCI is increased, how would
the system react?
NH4CI NH3 + HCI
A. Nothing would change.
B. The reaction would move to the right, producing more NH3.
C. The reaction would move to the left, producing more NH4CI.
D. There would only be HCI remaining.
Answer:
C.) The reaction would move to the left, producing more NH₄CI.
Explanation:
The chemical equation:
NH₄Cl ↔ NH₃ + HCl
If you were to increase the amount of HCl, the equilibrium would shift to the left. This is because the system is trying to go back to equilibrium. The equilibrium was disturbed when more product (HCl) was added. In order to restore equilibrium, you need to do the same thing that was done to the products to the reactants. In other words, since the products increased, the reactants need to increase.