Chemistry BYU

When 0.549 moles of a certain gas fill a balloon the volume is 75 mL. If enough of the same gas is added to the balloon until 1.44 moles of gas are present, what is the new volume of the balloon?

197 mL

Convert 2.58 x 1027 molecules CH3COOH (molecular weight 60 g/mol) to grams.

2.57 x 105 g

Convert 14.2 grams Pb(NO3)2 (molecular weight 331 g/mol) to molecules.

2.58 x 1022 molecules

Convert 3.6 x 102 atm to torr

2.7 x 105 torr

All of the following equations are statements of the ideal gas law except which? (see image 3-10)

P=nRTV

Boyle's law states which of the following?

Pressure and volume are inversely proportional.

The gas pressure inside a container decreases when which of the following happens?

the number of gas molecules is decreased

In the expression V = kn, n represents which of the following?

the number of moles of ga

What is Avogadro's number used to determine

the number of particles in 1 mole of a pure substance

The temperature and pressure at which a substance has all three states of matter (solid, liquid, and gas) in equilibrium is referred to as which of the following?

triple point

In a solution of salt and water, if the water can still dissolve more salt, the solution is described as which of the following?

unsaturated

Which of the following is defined as the gas pressure above a liquid at equilibrium?

vapor pressure

What is the most common solvent?

water

When does the boiling point of a liquid occur?

when the vapor pressure of the liquid equals the atmospheric pressure

What is the molecular mass of ammonium phosphate

149 g/mol

At 7°C, the volume of a gas is 49 mL. Assuming the pressure will remain constant, what will the temperature be if the volume of the gas is 74 mL?

150°C

The element europium (Eu) is named for the continent of Europe. What is the correct atomic weight of europium?

152 g/mol

Calculate the approximate temperature of a 0.50 mol sample of gas at 750 mm Hg and a volume of 12 L.

15°C

Convert -86°C to K.

187 K

The carbon-12 atom is assigned a relative mass of exactly what?

12 u

Calculate the approximate volume of a 0.600 mol sample of gas at 15°C and a pressure of 1.10 atm.

12.9 L

Find the molecular weight of Na2SO4.

142 g/mole

A sample of gas at 25°C has a volume of 11 L and exerts a pressure of 660 mm Hg. How many moles of gas are in the sample?

0.39 mol

Convert 42.7 grams Al(OH)3 (molecular weight 78 g/mol) to moles.

0.547 mol

Convert 156 kPa to mm Hg.

1.17 x 103mm Hg

Convert 1.62 atm to kPa.

1.64 X 102 kPa

Convert 1,246 torr to atm.

1.64 atm

Convert 296 K to °C.

23°C

What is the correct molecular weight of benzoyl peroxide (C14H10O4)?

242 g/mol

Convert the pressure 2.50 atm to kPa.

253 kPa

You are most likely sitting in a room that is about 298 K. What is this temperature of the room in Celsius?

25°C

A sample of oxygen occupies 320 mL when the pressure is 800 mm Hg. At constant temperature, what volume does the gas occupy when the pressure increases to 950 mm Hg?

270 mL

Standard temperature is defined as which of the following?

273 K

What is the correct molecular weight of vitamin A (C20H30O)?

286 g/mol

Convert 24°C to K.

297 K

What is the pressure exerted by 1.2 mol of a gas with a temperature of 20°C and a volume of 9.5 L?

3 atm

A hot day in July in Utah typically reaches 40 degrees C. What is this in Kelvin?

313 K

What is the mass of 2.0 mol of oxygen atoms (atomic mass 16.00 u)?

32 g

Convert 1.24 x 1024 molecules AgCH3COO (molecular weight 167 g/mol) to grams.

344 g

Find the molecular weight of K4Fe(CN)6

368 g/mol

If a sample of helium gas at 900 torr and 25°C is allowed to expand from 2.6 L to 5.8 L without changing the temperature, what pressure will the helium gas exert?

403 torr

Find the molecular weight of laughing gas, N2O.

44 g/mol

Find the molecular weight of As4O10.

460 g/mol

Convert 752 K to °C.

479°C

Find the molecular weight of Cs3PO4

494 g/mol

How many moles of air are there in a 125 mL flask if the pressure is 739 torr and the temperature is 18°C?

5.09 x 10-3 mol 8.22 x 10-2 mol

The volume of a gas is 5.0 L when the temperature is 5.0°C. If the temperature is increased to 10.0°C without changing the pressure, what is the new volume?

5.1 L

What is the mass of 1 mol of chromium (atomic mass 51.996 u)?

51.996 g

What is the number of atoms in 1 mol of carbon?

6.022 x 1023

Convert 3.94 x 1022 molecules KAl(SO4)2 (molecular weight 258 g/mol) to moles

6.54 x 10-2 mol

Convert 0.261 moles AsCl5 (molecular weight 253 g/mol) to grams.

6.60 X 101 g

In the figure displayed, what is the temperature and pressure of the critical point? (see image 2-19)

600°C and 12 atm

A sample of oxygen occupies 560 mL when the pressure is 800 mm Hg. At constant temperature, what volume does the gas occupy when the pressure decreases to 700 mm Hg?

640 mL

What is the boiling point of CHCl3if the atmospheric pressure on the surface of the liquid is 50 kPa? (see image 2-14)

64°C

A quantity of helium gas has a fixed volume, a pressure of 95 kPa, and a temperature of -25°C. When the temperature is decreased to -100°C, what is the new pressure of the helium gas?

66.3 kPa

Gallium is a metal that has a melting point just above room temperature but just lower than body temperature and literally melts in your hand when you pick it up. What is the correct atomic weight of gallium?

69.7 g/mol

Standard pressure is the pressure exerted by a column of mercury exactly how high?

760 mm

What is the mass of 8 atoms of copper in grams?

8.44 x 10-22 g

In the figure displayed, what is the temperature and pressure of the triple point? (see image 2-12)

80°C and 2 atm

How many atoms of calcium are present in 60.8 g of calcium

9.13 x 1023

The pressure of a quantity of gas at 10°C increases from 700 mm Hg to 900 mm Hg. What is the new temperature?

90.9°C

Convert 720 mm Hg to kPa.

96.0 kPa

The expression V = kn is a statement of which law?

Avogadro's law

The ideal gas law combines Boyle's law, Charles's law, Gay-Lussac's law, and what other law?

Avogadro's law

What is the number of atoms in a mole of any pure substance called?

Avogadro's number

You have two beakers on your lab table. Beaker 1 contains 32.07 g of sulfur and Beaker 2 contains 74.92 g of arsenic (As). Which beaker contains the greatest number of atoms? Choose the best answer.

Beakers 1 and 2 contain the same number of atoms because there is one mole in each.

All of the following gas laws are direct proportions except which of the following laws?

Boyle's law

The expression P = kT is a statement of which of the following laws?

Gay-Lussac's law

If you were asked to find the temperature using the ideal gas law, what would the formula be?

T = PV/nR

Denver is known as the "Mile High City" because its elevation above sea level is exactly 1 mile. Which of the following would explain why water boils at a lower temperature in Denver than at sea level?

The air pressure in Denver is lower, and this lower air pressure causes the boiling point to be lower than sea level.

Why does the equilibrium vapor pressure of a liquid increase with increasing temperature?

The average energy of the particles in the liquid increases

When a solute is placed in a solvent, which of the following does not occur? The freezing point is increased. The vapor pressure is lowered. The osmotic pressure is increased. The boiling point is increased.

The freezing point is increased.

In the figure displayed, if you move from point B to point A, what happens to this substance?(see image 2-19)

The substance cools, condenses to a liquid and freezes to a solid

Why does a can collapse when a vacuum pump removes the air from the can?

The unbalanced outside force from atmospheric pressure crushes the can.

If the temperature of a fixed quantity of a gas decreases and the pressure remains unchanged, which of the following will happen?

The volume of the gas will decrease

Ben is making dinner. The directions for his dinner ask him to place water in a pan and allow the atmospheric pressure pushing down on the water to be equaled by the vapor pressure of the water. This is just a fancy way of saying what?

The water should be boiling.

What can a polar substance dissolve?

a polar solute

The atomic number of neon is 10. The atomic number of calcium is 20. Compared with a mole of neon, how many atoms does a mole of calcium contain?

an equal number of atoms

Which instrument measures atmospheric pressure?

barometer

To convert a sample of air into a liquid as done commercially to produce liquid nitrogen, you would probably have to do which of the following?

decrease T, increase P

Which type of a water solution conducts electricity?

electrolyte

Which of the following would not affect the rate of solution of a solid in a liquid?

increasing the pressure on the solution heating the solution

Which of the following is the symbol used for the unit called a mole in chemistry?

mol

The value of R, the ideal gas constant, can be calculated from measured values of a gas's pressure, volume, temperature, and which of the following?

molar amount

When pressure, volume, and temperature are known, the ideal gas law can be used to calculate which of the following?

molar amount

Calculate the molar mass (molecular weight) of a sample if a single molecule weighs 9.19 x 10-23 g.

need correct answer number 18 on Lesson 1

At constant temperature and pressure, gas volume is directly proportional to which of the following?

number of moles of gas

Which of the following is not a solution?

oil and water

The relative atomic mass of an atom can be found by comparing the mass of the atom to the mass of what?

one atom of carbon-12

From the figure displayed, which is more dense: solid or liquid?(see image 2-19)

solid

When salt dissolves in water, which term describes the salt

solute

Which of the following is defined as a mixture in which one substance has dissolved uniformly throughout another substance?

solution

In a solution, what is the substance doing the dissolving, or the one in greater abundance?

solvent

Which of the following is defined as a phase change directly from solid to gas?

sublimation

Pressure is the force per unit of what?

surface area

At a constant volume, gas pressure is directly proportional to which of the following?

temperature

Water vapor pressure depends on which of the following?

temperature of the water

To determine the molecular mass of an element, one must know what about the element?

the atomic mass

Temperature is a measure of what?

the kinetic energy of the molecules