Chemistry Exam 3

What state(s) of matter is most compressible?

gas

a barometer measures

atmospheric pressure

Gas pressure is the result of

collision of gas particles with the walls of the container.

What statement conflicts with the kinetic molecular theory of gases?

Gas particles lose energy only when they collide when they collide with the walls of the container.

Polar gases exhibit more ideal behavior than non-polar ones

false

A given mass of oxygen at room temperature occupies a volume of 500.0 mL at 1.50 atm pressure. What pressure must be applied to compress the gas to a volume of only 150.0 mL?

PV=k

P=k/V

A balloon containing helium at constant pressure and temperature has the volume doubled by adding a more helium. Which statement(s) is(are) TRUE?

The number of moles of helium doubled.

The mass of helium in the balloon doubled.

The number of helium atoms doubled.

A sample of oxygen gas occupies 3.0 L at a pressure of 1.5 atm. If the volume of this sample increases without changing the temperature or the amount of gas, what can be said about the pressure?

The pressure of oxygen will be less than 1.5 atm.

Which of the following statements correctly describes Charles's Law?

The volume of a gas is directly proportional to the Kelvin temperature of the gas, if the pressure and amount of gas remain constant.

The density of hydrogen gas is lower than that of uranium hexafluoride (UF6) gas if both are measured at STP.

True

Which of the following is a statement of Dalton's law of partial pressure?

The total pressure of a mixture of gases is the sum of the partial pressure of each gas that makes up the mixture.

Consider 1.00 L of air in a patient's lungs at 37.0°C and 1.00 atm pressure. What volume would this air occupy if it were at 25.0°C under a pressure of 5.00 × 102 atm (a typical pressure in a compressed air cylinder)?

1.92 x 10-3 L

The temperature in which water boils inside a pressure cooker is lower than in an open pan at sea level.

False

What process is responsible for the formation of dew on the grass early in the morning?

condensation

Detergents and soaps decrease the surface tension of water.

True

Polar compounds generally have higher boiling points than non-polar compounds of similar molecular weight.

True

When acetone (a component of nail polish remover) evaporates, hydrogen bonds between acetone molecules must be broken up.

False

Which substance is expected to have the highest boiling point?

CH3OH

Which statement about a crystalline solid is always TRUE?

A crystalline solid has a regular repeating structure of the atoms, ions, or molecules that make up the solid.

Which property is typical for molecular solids?

have low melting points

The solubility of a solute is best described as which of the following?

the maximum amount of solute that can be dissolved in a specified amount of solvent

Which diagram best represents the composition of an aqueous calcium chloride (CaCl2) solution? (water molecules are not shown)

4 Cl- paticles/2 Ca2+ particles (B)

Which statement concerning solution concentration is TRUE?

If a bottle is labeled 0.10 M Ba(OH)2, the concentration of OH- ions in solution is 0.20 M.

An alloy, such as brass, is an example of a solution in the solid state.

True

Which statement concerning solutions is FALSE?

A solution forms when the solvent and the solute react to form a new substance with one uniform phase.

Ionic compounds are typically insoluble in water.

False

Calculate the mass in grams of NaCl that is present in 500.0 mL of a 0.900% (m/V) solution.

0.9 grams/100

5 x 0.9 = 4.5 grams

Calculate the concentration (% m/V) of NaCl solution that was made by dissolving 15.0 g of sodium chloride in enough water to make 300.0 mL of solution.

divide 15 by 300. Then multiply by 100. (5.00)

A solution contains 1.65 g of NaF in a total volume of 150.0 mL. What is its concentration expressed as % (m/V)?

divide 1.65 by 150. Then multiply by 100. (1.10)

How many moles of KCl are present in 50.0 mL of a 0.552 M solution?

multiply 50 by 0.552, then divide by 1,000. (0.0276)

What concentration term is defined as the number of moles of solute per kilogram of solvent in a solution?

molality

A chemist needs 0.725 moles of acetic acid for a particular reaction. What volume of a 1.50 M acetic acid solution is needed to provide this amount?

divide .725 by 1.5. (0.483 L)

A student needs to prepare 250.0 mL of a 2.50 M HCl solution using the stock solution 12.0 M HCl. What volume of 12.0 M HCl is required for this dilution?

multiply 250 by 2.50, then divide by 12. (52.1)

An aqueous solution containing a nonvolatile solute such as NaCl will have a freezing point above 0°C at 1 atm pressure.

False

What type of membrane allows solvent molecules to pass through but does not allow solute molecules to pass through?

semipermeable

What term is used to describe a solution of lower osmolarity compared to one with a higher osmolarity?

hypotonic

One mole of sodium chloride is added to 100 mL of water in beaker A. One mole of glucose, C6H12O6, is added to 100 mL of water in beaker B. How much more will the freezing point of water be lowered in beaker A than in beaker B?

twice as much

How are 0.15 M NaCl, 0.30 M glucose, and intracellular fluids similar?

They are all isotonic.

Ringer's solution is used in the treatment of burns and wounds. It is prepared by dissolving 8.6 g of NaCl, 0.30 g of KCl, and 0.33 g of CaCl2 in water, and diluting to a volume of 1.0 L. Which of the following is an accurate description of Ringer's solution?

Ringer's solution is an aqueous solution.

Vitamin D is essential for the normal development of teeth and bones. A tablet of Vitamin D is tested for its solubility in water and benzene. The results are shown in the table below. What is the most appropriate interpretation of the solubility results?

Vitamin D is likely a nonpolar substance.