Question 1

Using the ideal gas equation, find the pressure of 22.4L of helium at 273K when n=1.00 mol. Adjust this calculation using the real gas equation to find the actual pressure. What are the ideal and real pressures?

Accepted Answer

A)  1.00 atm, 1.20 atm
B)  1.0 atm, 1.00 atm
C)  1.5 atm, 1.20 atm
D)  1.5 atm, 1.00 atm
E)  2.0 atm, 1.20 atm

Question 2

Which of the following statements best explains why ice floats on water?

Accepted Answer

A)  Water has a higher specific heat than ice.
B)  Ice has the same molecular mass as water.
C)  Heat is absorbed when water changes from the solid state to the liquid state
D)  Hydrogen bonding causes water to be less dense in the solid state than in the liquid state.

Question 3

Which of the following statements best explains why water vapor condenses as temperature decreases?

Accepted Answer

A)  Collisions between water vapor molecules become elastic.
B)  Water vapor molecules chemically react when they collide.
C)  Water vapor molecules are pulled together by the force of gravity.
D)  Attractive forces between water vapor molecules overcome molecular motion.

Question 4

One way that mixtures differ from pure substances is in the methods that can be used to separate them into their components.Which of the following is a method used to separate the components of some mixtures?

Accepted Answer

A)  a nuclear reaction
B)  a filtration process
C)  a chemical reaction
D)  an electrolysis process

Question 5

Which of the following statements explains why the bond in hydrogen chloride (HCl)  is polar covalent?

Accepted Answer

A)  The atomic mass of chlorine is greater than that of hydrogen.
B)  The electronegativity of chlorine is greater than that of hydrogen.
C)  The diameter of a chlorine atom is greater than that of a hydrogen atom.
D)  The number of valence electrons in a chlorine atom is greater than that in a hydrogen atom.

Question 6

Which of the following statements describes properties of most metals?

Accepted Answer

A)  They have high melting and boiling points.
B)  They accept electrons to form negative ions.
C)  They have densities lower than that of water.
D)  They share electrons to form covalent bonds.

Question 7

Which of the following examples is evidence of a physical change?

Accepted Answer

A)  Ice cream melts in a bowl.
B)  A silver spoon tarnishes over time.
C)  An electrical current splits water into hydrogen and oxygen.
D)  A person inhales oxygen and exhales carbon dioxide and water.

Question 8

Which of the following observed properties is most reliable in classifying a substance as a metal?

Accepted Answer

A)  good conductor of heat
B)  low melting temperature
C)  unreactive with other elements
D)  crumbles when hit by a hammer

Question 9

Which of the following occurs when a rigid container of gas is heated?

Accepted Answer

A)  The pressure inside the container increases.
B)  The pressure inside the container decreases.
C)  The pressure inside the container stays the same.
D)  The pressure inside the container changes the composition of the gas.

Question 10

Which of the following activities could cause liquid molecules to overcome intermolecular attractive forces and become gas molecules?

Accepted Answer

A)  adding a solute to the liquid
B)  adding a catalyst to the liquid
C)  increasing the temperature of the liquid
D)  increasing the air pressure above the liquid

Question 11

A hospital buys a compound that contains an isotope of barium. Several months later, most of the barium has changed to the element lanthanum. Which of the following is responsible for this change?

Accepted Answer

A)  exposure to air
B)  radioactive decay
C)  reactions with the container wall
D)  absorption of moisture from the air

Question 12

Two elements in a molecule have the same electronegativity values. Which of the following most likely holds the elements together and why?

Accepted Answer

A)  an ionic bond, because electrons transfer from one element to the other
B)  a nonpolar covalent bond, because the elements share electrons equally
C)  a polar covalent bond, because the elements do not share electrons equally
D)  an intermolecular force, because the elements do not form a chemical bond

Question 13

Which of the following pieces of evidence best supports Bohr's idea that electrons occupy specific energy levels within an atom?

Accepted Answer

A)  Sodium atoms become positive ions when they lose electrons.
B)  Each element emits a unique brightline spectrum when it falls from an excited state to a ground state.
C)  Beryllium atoms bombarded with alpha particles produce beams that are not influenced by magnetic fields.
D)  Each element has physical and chemical properties that are unique to that element and different from those of other elements.

Question 14

Concrete is composed of Portland cement, rocks, sand, and water. Which of the following best describes concrete?

Accepted Answer

A)  an element
B)  a compound
C)  a homogenous mixture
D)  a heterogeneous mixture

Question 15

A gas enters a compressor where it is converted to a liquid. Which of the following happens to the gas as it becomes a liquid?

Accepted Answer

A)  It loses mass.
B)  It releases heat.
C)  It loses protons.
D)  It releases electricity.

Question 16

Which of the following lists three states of water in order of increasing entropy?

Accepted Answer

A)  ice, liquid, vapor
B)  liquid, ice, vapor
C)  ice, vapor, liquid
D)  vapor, liquid, ice

Question 17

Molal concentration, m, is expressed as (kilograms of solute) / (kilograms of solvent).

Accepted Answer

A) True 
 B)False

Question 18

CH3COOH + H2O --> CH3COO- + H3O+
Which of the following descriptions best characterizes CH3COO- in the reaction above?

Accepted Answer

A)  Cation
B)  Conjugate acid
C)  Conjugate base
D)  Indicator
E)  Neutral species

Question 19

Na+ --> Na2+ + e- 
The reaction above is endothermic.

Accepted Answer

A) True 
 B)False

Question 20

Which of the following correctly pairs a phase of matter with its description?

Accepted Answer

A)  Solid: Particles have no motion.
B)  Liquid: Particles expand to fill any container in which they are placed.
C)  Gas: Particles have higher amounts of energy than when in the liquid phase.
D)  Liquid: Particles are more strongly attached to one another than when in the solid phase.

Exam 2: Chemistry

Which of the following examples is evidence of a physical change?

Correct AnswerverifiedShow Answer

Molal concentration, m, is expressed as (kilograms of solute) / (kilograms of solvent).

Correct AnswerverifiedShow Answer

Which of the following correctly pairs a phase of matter with its description?

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Which of the following observed properties is most reliable in classifying a substance as a metal?

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A gas enters a compressor where it is converted to a liquid. Which of the following happens to the gas as it becomes a liquid?

Correct AnswerverifiedShow Answer

Which of the following statements best explains why ice floats on water?

Correct AnswerverifiedShow Answer

Two elements in a molecule have the same electronegativity values. Which of the following most likely holds the elements together and why?

Correct AnswerverifiedShow Answer

Which of the following statements best explains why water vapor condenses as temperature decreases?

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Which of the following lists three states of water in order of increasing entropy?

Correct AnswerverifiedShow Answer

A hospital buys a compound that contains an isotope of barium. Several months later, most of the barium has changed to the element lanthanum. Which of the following is responsible for this change?

Correct AnswerverifiedShow Answer

Which of the following pieces of evidence best supports Bohr's idea that electrons occupy specific energy levels within an atom?

Correct AnswerverifiedShow Answer

Which of the following activities could cause liquid molecules to overcome intermolecular attractive forces and become gas molecules?

Correct AnswerverifiedShow Answer

Using the ideal gas equation, find the pressure of 22.4L of helium at 273K when n=1.00 mol. Adjust this calculation using the real gas equation to find the actual pressure. What are the ideal and real pressures?

Correct AnswerverifiedShow Answer

Concrete is composed of Portland cement, rocks, sand, and water. Which of the following best describes concrete?

Correct AnswerverifiedShow Answer

One way that mixtures differ from pure substances is in the methods that can be used to separate them into their components.Which of the following is a method used to separate the components of some mixtures?

Correct AnswerverifiedShow Answer

Which of the following statements explains why the bond in hydrogen chloride (HCl) is polar covalent?

Correct AnswerverifiedShow Answer

CH3COOH + H2O --> CH3COO- + H3O+ Which of the following descriptions best characterizes CH3COO- in the reaction above?

Correct AnswerverifiedShow Answer

Which of the following occurs when a rigid container of gas is heated?

Correct AnswerverifiedShow Answer

Which of the following statements describes properties of most metals?

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Na+ --> Na2+ + e- The reaction above is endothermic.

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CH₃COOH + H₂O --> CH₃COO^- + H₃O⁺ Which of the following descriptions best characterizes CH₃COO^- in the reaction above?

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Na⁺ --> Na²⁺ + e^- The reaction above is endothermic.

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