Chemistry Unit 5 Exam

If the percentage yield for the reaction represented by the following equation is calculated to be 75.3%, what mass of Al is expected from the reaction of 52.5g of Al2O3?

20.9 g Al

For the equation P4(s)+5O2(g)->P4O10(s), if 3 mol of phosphorus react with 10 mol of oxygen, the theoretical yield of phosphorus(v) oxide will be

3 mol

What is the mole ratio of H2O to H3PO4 in the following chemical equation? P4O10+6H2O->4H3PO4

3 to 2

In the equation 2Al2O3->4Al+3O2, what is the mole ratio of aluminum to oxygen?

4:3

For the reaction represented by the equation SO3+H2O->H2SO4, what is the percentage yield of 500g of sulfur trioxide react with excess water to produce 575g of sulfuric acid?

93.9%

Under which conditions does a real gas behave very much like an ideal gas?

At High temperatures and low pressure

Which of the following mathematical expressions correctly states the relationship among percentage yield, actual yield, and theoretical yield?

Both (b) and (c)

Liquids and solids are much denser than gases because the particles of liquids and solids have a

Closer arrangment

For a chemical reaction, percentage yield represents the

Efficiency

Which gas is most likely to deviate from ideal gas behavior?

NH3

According to the equation for the kinetic energy of a moving object, which gas would have the lowest average velocity, assuming all gases are at the same temperature.

O3

An increase in pressure exerted on a liquid does not compress the liquid as much as the same increase in pressure compresses a gas because

Particles are more closely packed in liquids

Which of the following factors does not affect the actual yield of a reaction?

Particles no longer reacting with each other.

Amorphous solids behave like liquids at certain temperatures because of their

Random arrangements

A solid's molar enthalpy of fusion is the energy that is

absorbed when a solid melts

One mole of benzene vapor condenses at its boiling point. The amount of energy released by the benzene as it completely condenses is known as its molar

enthalpy of vaporization

In general, ionic compounds have

high boiling points and high melting points

The actual yield of a chemical reaction is generally

less than the theoretical yield

If the particles in a sample of matter are attracted to each other but can move pas each other easily, the matter is

liquid

Which expression can be used to solve a mass-to-mole conversion for the equation 2HCl-->H2+Cl2

mass HCl x 1 mol HCl/molar mass HCl x 1 mol Cl2/2 mol HCl

The expression mass*(1mol/molar mass) has the unit

mol

A balanced chemical equation allows one to determine the

mole ratio of any two substances in the reaction

A phase diagram relates the state of matter, pressure, and

temperature

Covalent molecular crystals have very low melting points, while covalent network crystals have very high melting points because

the forces that hold molecules together in molecular crystals are weaker than those that hold molecules or atoms together in network crystals

If a gas and a liquid are at the same temperature and pressure, diffusion occurs much faster in the gas because

the particles move faster in the gas and there is greater distance between them

Fewer steps are required to solve stoichiometry problems when

the reactant is given in moles and the product is sought in moles

The limiting reactant of a reaction can be used to calculate the

theoretical yield

On a phase diagram, the point at which all equilibrium lines join is the

triple point

A sample of carbon dioxide gas is in equilibrium with solid dry ice. If the temperature of the system increases,

vapor pressure of the gas increases

Which of the following expressions is not a legitimate conversion factor?

1 g C/6.022 x 10^23 atomsC