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Which is evidence that a chemical reaction has likely occurred?
a liquid slowly losing volume
the formation of a precipitate
boiling water releasing steam
a change in the shape of a solid
Answer:
The new substance will need more energy to form its chemical bonds than the old substance will release. ... More energy will be released from the old substance than the new substance will need to form its chemical bonds.
Explanation:
This is the answer I got. Hope it's really helpful
Answer:
"Which is evidence that a chemical reaction has likely occurred?"
The correct answer would be,
B. the formation of a precipitate
Explanation:
Got it right on my test, have a great day!
Equal mases of ethane and hydrogen are mixed in an empty container at 25 degree celcius.The fraction of the total pressure exerted by hydrogen is
Answer:
15/16
Explanation:
We need to find the number of moles of hydrogen and number of moles of ethane present.
Since we have the same mass, m for both substances, the number of moles of hydrogen, n = m/M where M = molar mass of hydrogen molecule
Since hydrogen is H₂, M = 2 × 1 g/mol = 2 × 1 g/mol = 2 mol.
n = m/M
n = m/2
Also, number of moles of ethane, n' = m/M' where M' = molar mass of ethane.
Since ethane is C₂H₆, M' = 2 × 12 g/mol + 6 × 1 g/mol = 24 g/mol + 6 g/mol = 30 g/mol
n' = m/M'
n' = m/30
The total number of moles of gas present is thus n" = n + n' = m/2 + m/30 = (15m + m)/30 = 16m/30
The mole fraction of hydrogen is thus number of moles of hydrogen/total number of moles = n/n" = m/2 ÷ 16m/30 = m/2 × 30/16m = 15/16
Also, since the partial pressure due to hydrogen, P = mole fraction × total pressure, P'
P/P' = mole fraction = 15/16
So, The fraction of the total pressure exerted by hydrogen is 15/16
what is the chemical name for NH4?
Answer:
Ammonium Ion (NH4+)
Explanation:
The chemical name for NH4 is ammonium.
Use the average acceleration obtained in Activity 1 to determine how far the ball should drop at 0.3 second, 0.5 second, and 0.7 second. Using the simplified formula y = 1/2 at2 (because y0 = 0 and v0 = 0), calculate y to one decimal place.
Answer:
0.3 sec : -0.4 m
0.5 sec: -1.2 m
0.7 sec: -2.3 m
Explanation:
0.3 sec: 1/2(-9.3 m/s^2)(0.3 s)^2 = -0.4 m
0.5 sec: 1/2(-9.3 m/s^2)(0.5 s)^2 = -1.2 m
0.7 sec: 1/2(-9.3 m/s^2)(0.7 s)^2 = -2.3 m
Which is a property of all acids?
A. They increase the OH^- concentration in solution.
B. They contain OH^- ions.
C. They contain H3O^+ ions.
D. They increase the H^+ concentration in solution.
Acids increase the [tex]H^+[/tex] concentration in solution. Therefore, the correct option is D.
One of their essential characteristics is the ability of all acids to increase the concentration of H+ ions (protons) in a solution. Acids are chemicals that when dissolved in water add protons to the solution. As a result of this proton donation, the amount of [tex]H^+[/tex]ions in the solution increases, thereby lowering the pH. It is important to remember that not all acids contain[tex]H_3O^+[/tex] ions directly; Instead, [tex]H^+[/tex] ions can react with water molecules to generate [tex]H_3O^+[/tex] ions (hydronium ions).
Therefore, the correct option is D.
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How much of the original amount of an isotope is present after a period of two half-lives?
A. Four times the original amount
B. One-fourth of the original amount
C. Twice the original amount
D. Half of the original amount
One-fourth of the original amount of an isotope is present after a period of two half-lives as each time the amount is reduced by half.
What is an isotope?Isotopes are defined as substances having same number of protons but different number of neutrons.Number of protons is characteristic for determining position of elements in the periodic table.
Since,all isotopes have the same number of protons and hence have same position.They have similar chemical properties as they have same number of electrons.
They find applications in the field of nuclear medicine and oil and gas research . There are 2 types of isotopes : stable and unstable
Unstable isotopes are radioactive and are called as radioisotopes.Some of these isotopes are man -made and hence also called as artificial isotopes.Every element has an isotope which is either man-made or natural .
Many properties of isotopes depend on mass which is measured in atomic mass unit. The difference in actual mass and mass number is called mass defect.
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What mass of sulfuric acid, H2SO4, is required to react with 3.27 g of potassium hydroxide, KOH? The products of this reaction are potassium sulfate and water.
Have both the unbalanced and balanced chemical equations.
Explain how to find the molar mass of the compounds.
Explain how the balanced chemical equation is used to find the ratio of moles
Explain how many significant figures your answer needs to have.
The numerical answer
Answer:
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Don't plagiarize here.
Explanation:
Your online teacher knows that you are looking here for the answer!!!!
calculate the volume of a 3.0 mol of oxygen, b 50.0g of hydrogen cloride gas at STP(molar volume of gas is 22.4dm³,molar mass of Hcl=36.5g)
Answer:
98L is the volume of the gas
Explanation:
To solve this question we need to find the moles of O2 + moles HCl. With these moles and PV = nRT we can find the volume as follows:
Moles O2: 3.0mol
Moles HCl:
50.0g * (1mol/36.5g) = 1.37 moles HCl
Total moles:
3.0mol O2 + 1.37 mol HCl = 4.37 moles
PV = nRT
V = nRT/P
Where V is volume in L, n are moles = 4.37mol, R is gas constant = 0.082atmL/molK, T is absolute temperature = 273.15K at STP, P = 1atm at STP
V = 4.37mol*0.082atmL/molK*273.15K / 1atm
V = 98L is the volume of the gas
Given that the acceleration due to gravity is 10N/Kg, calculate the weight of the
Mass (Show all you're working)
Answer:
Weight = 500 Newton
Explanation:
Given the following data;
Acceleration due to gravity = 10N/Kg
Weight can be defined as the force acting on a body or an object as a result of gravity.
Mathematically, the weight of an object is given by the formula;
[tex] Weight = mg [/tex]
Where;
m is the mass of the object.g is the acceleration due to gravity.Note: In order to calculate the weight of a mass, it's required that the mass of an object or body is given.
However, in this particular question it was omitted in error and as such i would assume a value.
Let mass, m = 50 kgSubstituting into the formula, we have;
[tex] Weight = 50 * 10 [/tex]
Weight = 500 Newton
The chemical reaction between the reagents luminol and bleach produces a brief flash of light. Which change would most likely make the light produced in the reaction last longer?
increasing luminol concentration
adding a catalysts
decreasing the quantity of both reagents.
decreasing the temperature
Here is a word equation for a chemical reaction.
copper oxide + sulphuric acid
---> copper sulphate + water
Write down everything that the word equation tells you about the reaction.
Explanation:
From the word equation, it shows that when copper oxide reacts with sulphuric acid, a double replacement reaction will occur, where copper and sulphate forms a bond with each other, and so do water.
The reaction of copper oxide with sulphuric acid to form copper sulphate and water can be written as follows: [tex]CuO + H_{2}SO_{4} \rightarrow CuSO_{4} + H_{2}O[/tex]
What is a balanced reaction?In a balanced chemical reaction all the reactants will be in a correct stochiometric ratios where, each elements have to be equal in number on both side of the reaction.
The given reaction is an example of double displacement reaction in which two species are displaced. Here, oxygen from copper oxide goes to water and sulphate group from sulphuric acid displace to copper sulphate.
This product of this reaction i.e., copper sulphate have cyan color and this reaction is exothermic. Thus, the balanced reaction can be written as follows;
[tex]CuO + H_{2}SO_{4} \rightarrow CuSO_{4} + H_{2}O[/tex]
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The atomic number and the mass number of 18 and 40. Write the information conveyed by this statement.
1.875mps into kilometers per hour
Answer:
6,75 kilometres per hour
The temperature of a sample of liquid water changes from 50°C to 30°C. Which statement best explains the change
that must happen at the molecular level?
The molecules move more quickly and their average kinetic energy increases
The molecules move more bowly and their average kinetic energy decreases
The molecules move more quickly and their average kinetic energy decreases
The molecules move more slowly and their average kinetic energy increases.
Answer:
The molecules move slower than the temp of 50°c and their average kinetic energy decreases.
Explanation:
kinetic energy cannot increase as temperature is reduced. molecules will still move with reduced motion.
Which of the following are 'natural polymers
(bio-molecules)? Choose all that apply.
nylon
teflon
silk
cellulose
proteins
polyethylene
SOMEONE PLEASE HELP ME!
I will give brainliest
Answer:
1.B
2.C
3.D
Explanation:
In the first question, the valence in XH4 belongs to the X. So when it reacts with oxygen with always a valence of two, they cancel out remaining 2 making it XO2.
In the second question the 2 belongs to Y as we all know Sodium is atomic number 11 with a valence of one, so they exchanged valence.
When Y2 reacts with chlorine with atomic number 17 and valence 1,they exchange valencies making it YCl2.
In the third question, 2belongs to Y, so when it reacts with aluminum with atomic number 13 and valence 3,they exchange valencies making it Al2Y3
The relative atomic mass of helium is 4 and the relative atomic mass of bromine is 80. How many helium atoms will be as one bromine atom?
Answer:
80÷4=20 Helium atoms
Explanation:
Because one helium atom is a quarter of of one bromine atom
Which method of separation would you use, if you want to collect.....A.Some sugar from a sugar solution? B.Rice grains, which have accidentally been mixed with flour? C.Some pure water from salty water?D.Some salt from salty water?E.Some clear water from muddy water?
Answer:
Explanation:
B.Rice grains, which have accidentally been mixed with flour
Which of the following is an example of commensalism?
Answer: A tick on a deer
Explanation:
because commensalism is a type of symbiotic relationship in which one species benefits, while the other species is neither harmed nor helped
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An example of commensalism is tick on a deer. Therefore, option A is correct.
What is commensalism ?Another sort of symbiotic interaction is commensalism, in which one organism benefits and the other does not in any way suffer. Golden jackals will pursue tigers as they hunt in order to consume the tigers' leftovers.
The term "commensalism" is derived from the word "commensal," which in human social interaction refers to "eating at the same table," and which itself is derived through French from the Medieval Latin term "commensalis," which refers to "sharing a table," from the prefix com-, which means "together," and mensa, which refers to "table" or "meal."
The simplest definition of commensalism is that it is a form of symbiosis in which one organism gains while the other neither gains nor suffers harm. The three primary forms of commensalism are phoresy, metabiosis, and inquilinism.
Thus, option A is correct.
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How many moles are in 89 grams of KCI
Answer:
The number of moles in 89 grams of KCl is approximately 1.193 moles
Explanation:
A mole of an element or compound, is the quantity of the element or compound that contains 6.022 × 10²³ molecules of the element or compound, such that the molar mass of one mole is dependent on the mass of each molecule of the element or compound that make up the 6.022 × 10²³ particles
The given parameters are;
The mass of the KCl = 89 grams
The Molar mass, MW, of potassium, K = 39.1 g/mole
The Molar mass, MW, of chlorine, Cl = 35.5 g/mole
Therefore, given that KCl, has one K and one Cl, per mole, we have;
The Molar mass, MW, of potassium chloride, KCl = (39.1 + 35.5) g/mole = 74.6 g/mole
[tex]The \ number \ of \ moles, n=\dfrac{Mass}{Molar \ mass, MW}[/tex]
Therefore, the number of moles of KCl in 89 g, 'n' is given as follows;
n = (89 g)/(74.6 g/mole) ≈ 1.193 moles
The number of moles in 89 grams of KCl, n ≈ 1.193 moles.
what do you mean by chemical reaction
Answer:
Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products.
A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.
Chemical reactions are an integral part of technology, of culture, and indeed of life itself. Burning fuels, smelting iron, making glass and pottery, brewing beer, and making wine and cheese are among many examples of activities incorporating chemical reactions that have been known and used for thousands of years. Chemical reactions abound in the geology of Earth, in the atmosphere and oceans, and in a vast array of complicated processes that occur in all living systems.
Explanation:
hope it help
plss brainlys me
Answer:
Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products
Explanation:
Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.
On increasing which of the following factors, decreases the extent of physisorption? Surface area of the adsorbent Critical temperature of the adsorbate Concentration of adsorbate Temperature at which adsorption is carried out
Answer: On increasing temperature at which adsorption is carried out decreases the extent of physisorption.
Explanation:
An adsorption where molecules of the adsorbate are placed or held on the surface of adsorbent by Vander waals forces is called physisorption.
There is basically physical bonding between the molecules of gas to the surface of a solid or liquid.
Physisorption is reversible in nature and occurs at low temperatures.
It is not specific in nature which means that all gases are adsorbed on the surface of every solid substance to some extent.
Thus, we can conclude that on increasing temperature at which adsorption is carried out decreases the extent of physisorption.
What is microorganisms
Answer:
Technically a microorganism or microbe is an organism that is microscopic. The study of microorganisms is called microbiology. Microorganisms can be bacteria, fungi, archaea or protists. The term microorganisms does not include viruses and prions, which are generally classified as non-living.
Obtener la fórmula empírica de un compuesto cuya composición centesimal reporta: Cr: 26,53 % , S: 24,52 % y O: 48,96%. Dato: m.A. [Cr= 52 , S= 32]
Respuesta:
Cr₂S₃O₁₂
Explicación:
Primer paso: Dividir el porcentaje en masa de cada elemento por su masa atómica
Cr: 26,53/52 = 0,510
S: 24,52/32 = 0,766
O: 48,96/16 = 3,06
Segundo paso: Dividir todos los números por el más pequeño (0,510)
Cr: 0,510/0,510 = 1
S: 0,766/0,510 = 1,5
O: 3,06/0,510 = 6
Tercer paso: Multiplicar todos los números por algún número que haga que todos sean enteros (2)
Cr: 1 × 2 = 2
S: 1,5 × 2 = 3
O: 6 × 2 = 12
La fórmula empírica es Cr₂S₃O₁₂.
Answer: The empirical formula of the compound becomes [tex]Cr_2S_3O_{12}[/tex]
Explanation:
The empirical formula is the chemical formula of the simplest ratio of the number of atoms of each element present in a compound.
Let the mass of the compound be 100 g
Given values:
% of Cr = 26.53%
% of S = 24.52%
% of O = 48.96%
Mass of Cr = 26.53 g
Mass of S = 24.52 g
Mass of O = 48.96 g
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
To formulate the empirical formula, we need to follow some steps:
Step 1: Converting the given masses into moles.Molar mass of Cr = 52 g/mol
Molar mass of S = 32 g/mol
Molar mass of O = 16 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of Cr}=\frac{26.53g}{52g/mol}=0.510 mol[/tex]
[tex]\text{Moles of S}=\frac{24.52g}{32g/mol}=0.766 mol[/tex]
[tex]\text{Moles of O}=\frac{48.96g}{16g/mol}=3.06 mol[/tex]
Step 2: Calculating the mole ratio of the given elements.Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 0.510 moles
[tex]\text{Mole fraction of Cr}=\frac{0.510}{0.510}=1[/tex]
[tex]\text{Mole fraction of S}=\frac{0.766}{0.510}=1.5[/tex]
[tex]\text{Mole fraction of O}=\frac{3.06}{0.510}=6[/tex]
Multiplying the mole fraction of all the elements by 2, in order to make it as a whole number
[tex]\text{Mole fraction of Cr}=(2\times 1)=2[/tex]
[tex]\text{Mole fraction of S}=(2\times 1.5)=3[/tex]
[tex]\text{Mole fraction of O}=(2\times 6)=12[/tex]
Step 3: Taking the mole ratio as their subscripts.The ratio of Cr : S : O = 2 : 3 : 12
Hence, the empirical formula of the compound becomes [tex]Cr_2S_3O_{12}[/tex]
Given the reaction: HSO4–(aq) + NH3(g) --> NH4+(aq) + SO42–(aq), which statement best describes the action of NH3(g) in the reaction?
Answer: NH3 (g) would be considered a base because it is a proton acceptor.
Explanation: at the end of the system, NH3 (g) turns into NH4+ (aq) which means it has accepted a hydrogen ion.
According to Bronsted- Lowry concept, bases are proton acceptors. Here, NH₃ is accepting a proton from HSO₄⁻. Hence, NH₃ is a base and option B is correct.
What is Bronsted- Lowry concept of acids and bases ?There are various concepts to define acids and bases. According to Bronsted - Lowry concept, acids are proton donors and bases are proton acceptors.
Acids forms their conjugate base by donating a proton and bases form their conjugate acid by accepting the proton from acid. Here, HSO₄⁻ acts as the acid to donate electron to ammonia.
Hence, NH₃ acts as the base to accept the proton from the acid and forms its conjugate acid NH₄⁺ (ammonium ion). Therefore, option B describes the action of NH₃.
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Your complete question is given below:
Which of these describes why a stent is used?
A stent is a small mesh tube that holds open passages in the body, such as weak or narrow arteries.
Explanation:
To open an artery near the heart
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Pls Answer
What happens when dilute sulphuric acid is poured on a copper plate ?
Answer:
No observable change.
Explanation:
Copper renders dilute sulphuric acid passive, no reaction.
H2SO4+Cu-->CuSO4+H2
Explanation:
THIS IS THE CORRECT ANSWER
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Answer:
See explanation
Explanation:
The can chiller has a cooling system which expels heat around the immediate vicinity of the can chiller.
Let us remember that convection is a mode of heat transfer that occurs as a result of the actual movement of the particles of a substance. In this case, we are going to consider the movement of air molecules.
As the can chiller expels heat, the air molecules around the can chiller become heated and less dense and begin to move away from the can chiller. They are quickly replaced by cold denser air.
This process of cycling of hot/cold air molecules is known as a convection current. It is set up as a result of the working of the can chiller.
Compare the stability of primary, secondary and tertiary carbocation
Answer:
Primary carbocations are most stable, Secondary carbocations are more stable, tertiary carbocations are least stable.
Explanation:
This is due to Asterric hinderance.
12. If a reaction is exothermic,
a) It takes more energy to break the bonds of the reactants than is released when the bonds in
the products are formed
b) More energy is released when the bonds in the products are formed than is used to break
the bonds in the reactants
c) The same amount of energy is used to break the bonds of the reactants as is
released when the bonds in the products are formed
d) The temperature goes down
Answer:
In the case of an exothermic reaction, the reactants are at a higher energy level as compared to the products, as shown below in the energy diagram. In other words, the products are more stable than the reactants. Overall Δ H ΔH ΔH for the reaction is negative, i.e., energy is released in the form of heat.
Explanation: