Question 1

Why is heat often added to chemical reactions performed in the laboratory?

Accepted Answer

A) to allow a greater number of reactants to pass over the activation energy 
B) to increase the rate at which reactant collide 
C) to compensate for the natural tendency of energy to disperse 
D) all of the above 
A) to allow a greater number of reactants to pass over the activation energy 
B) to increase the rate at which reactant collide 
C) to compensate for the natural tendency of energy to disperse 
D) all of the above

Question 2

The portion of the atmosphere that filters out 95 percent of the incident UV radiation is the ________.

Accepted Answer

A) ozone layer 
B) stratosphere 
C) troposphere 
D) aerosol layer 
E) particulates 
A) ozone layer 
B) stratosphere 
C) troposphere 
D) aerosol layer 
E) particulates

Question 3

There are 1000 liters in 1 cubic meter and 1000 grams in 1 kilogram. How many grams of air are there in 1.00 liter of air? (Assume a density of 1.25 kg/   .)

Accepted Answer

A) 0.00125 gram 
B) 0.125 gram 
C) 1.25 grams 
D) 12.5 grams 
A) 0.00125 gram 
B) 0.125 gram 
C) 1.25 grams 
D) 12.5 grams

Question 4

According to the following balanced chemical equation, if you want to generate two moles of H2O, how many moles of O2 do you need? 2 H2 + O2 → 2 H2O

Accepted Answer

A) 1 
B) 2 
C) 1/2 
D) 4 
E) 6.022 × 1023 
A) 1 
B) 2 
C) 1/2 
D) 4 
E) 6.022 × 1023

Question 5

Which of the following has the greatest mass?

Accepted Answer

A) 1 mole of Pb 
B) 1 mole of H2 
C) 1 mole of Be 
D) 1 mole of Na 
E) All have the same mass. 
A) 1 mole of Pb 
B) 1 mole of H2 
C) 1 mole of Be 
D) 1 mole of Na 
E) All have the same mass.

Question 6

What happens to the entropy of a system as the components of the system are introduced to a larger number of possible arrangements, such as when liquid water transforms into water vapor?

Accepted Answer

A) The entropy decreases because there are less ways in which the energy can disperse. 
B) The entropy increases because there are more ways in which the energy can disperse. 
C) The entropy of a system is independent of introducing the components of the system to a larger number of possible arrangements. 
D) The entropy of a system is solely dependent upon the amount of material undergoing reaction. 
A) The entropy decreases because there are less ways in which the energy can disperse. 
B) The entropy increases because there are more ways in which the energy can disperse. 
C) The entropy of a system is independent of introducing the components of the system to a larger number of possible arrangements. 
D) The entropy of a system is solely dependent upon the amount of material undergoing reaction.

Question 7

Which has more atoms: 17.031 g of ammonia, N   (17.031 amu), or 72.922 g of hydrogen chloride, HCl (36.461 amu)?

Accepted Answer

A) 17.031 g of N   has more atoms than 72.922 g of HCl 
B) 72.922 g of HCl has more atoms than 17.031 g of N   
C) 72.922 g of HCl and 17.031 g of N   have about the same number of atoms. 
D) Not enough information is given. 
A) 17.031 g of N   has more atoms than 72.922 g of HCl 
B) 72.922 g of HCl has more atoms than 17.031 g of N   
C) 72.922 g of HCl and 17.031 g of N   have about the same number of atoms. 
D) Not enough information is given.

Question 8

The ________ is what needs to be overcome in a reaction so that it can proceed to the products.

Accepted Answer

A) activation energy 
B) catalyst 
C) entropy 
D) thermodynamics 
E) bond energy 
A) activation energy 
B) catalyst 
C) entropy 
D) thermodynamics 
E) bond energy

Question 9

Is it possible to have a macroscopic sample of oxygen that has a mass of 14 atomic mass units?

Accepted Answer

A) Yes, but it would need to be made of oxygen atoms that each had less than the normal number of neutrons. 
B) No, this is less than than the mass of a single oxygen atom. 
C) Yes, but it would have the same density as nitrogen. 
D) No, because oxygen is a gas at room temperature. 
A) Yes, but it would need to be made of oxygen atoms that each had less than the normal number of neutrons. 
B) No, this is less than than the mass of a single oxygen atom. 
C) Yes, but it would have the same density as nitrogen. 
D) No, because oxygen is a gas at room temperature.

Question 10

Which of the following is a correctly balanced equation?

Accepted Answer

A) P4 + 6 H2 → 4 PH3 
B) 1 P4 + 6 H2 → 4 PH3 
C) 0 P4 + 6 H2 → 4 PH3 
D) 2 P4 + 12 H2 → 8 PH3 
E) P4 + 3 H2 → PH3 
A) P4 + 6 H2 → 4 PH3 
B) 1 P4 + 6 H2 → 4 PH3 
C) 0 P4 + 6 H2 → 4 PH3 
D) 2 P4 + 12 H2 → 8 PH3 
E) P4 + 3 H2 → PH3

Why is heat often added to chemical reactions performed in the laboratory?

The portion of the atmosphere that filters out 95 percent of the incident UV radiation is the ________.

There are 1000 liters in 1 cubic meter and 1000 grams in 1 kilogram. How many grams of air are there in 1.00 liter of air? (Assume a density of 1.25 kg/ .)

According to the following balanced chemical equation, if you want to generate two moles of H₂O, how many moles of O₂ do you need? 2 H₂ + O₂ → 2 H₂O

Which of the following has the greatest mass?

What happens to the entropy of a system as the components of the system are introduced to a larger number of possible arrangements, such as when liquid water transforms into water vapor?

Which has more atoms: 17.031 g of ammonia, N (17.031 amu), or 72.922 g of hydrogen chloride, HCl (36.461 amu)?

The ________ is what needs to be overcome in a reaction so that it can proceed to the products.

Is it possible to have a macroscopic sample of oxygen that has a mass of 14 atomic mass units?

Which of the following is a correctly balanced equation?

About Science

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Subatomic Particles

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How Atoms Bond

How Molecules Mix

How Water Behaves

Acids and Bases in Our Environment

Oxidations and Reductions Charge the World

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Exam 9: How Chemicals React

Why is heat often added to chemical reactions performed in the laboratory?

The portion of the atmosphere that filters out 95 percent of the incident UV radiation is the ________.

There are 1000 liters in 1 cubic meter and 1000 grams in 1 kilogram. How many grams of air are there in 1.00 liter of air? (Assume a density of 1.25 kg/ .)

According to the following balanced chemical equation, if you want to generate two moles of H2O, how many moles of O2 do you need? 2 H2 + O2 → 2 H2O

Which of the following has the greatest mass?

What happens to the entropy of a system as the components of the system are introduced to a larger number of possible arrangements, such as when liquid water transforms into water vapor?

Which has more atoms: 17.031 g of ammonia, N (17.031 amu), or 72.922 g of hydrogen chloride, HCl (36.461 amu)?

The ________ is what needs to be overcome in a reaction so that it can proceed to the products.

Is it possible to have a macroscopic sample of oxygen that has a mass of 14 atomic mass units?

Which of the following is a correctly balanced equation?

About Science

Particles of Matter

Elements of Chemistry

Subatomic Particles

The Atomic Nucleus

How Atoms Bond

How Molecules Mix

How Water Behaves

Acids and Bases in Our Environment

Oxidations and Reductions Charge the World

Organic Compounds

Nutrients of Life

Medicinal Chemistry

Optimizing Food Production

Protection Water and Air Resources

Capturing Energy

Filters

According to the following balanced chemical equation, if you want to generate two moles of H₂O, how many moles of O₂ do you need? 2 H₂ + O₂ → 2 H₂O