Module 10

Question 1

When you dissolve sodium fluoride in water, which compound is the solute and which is the solvent?

Answer 1

Sodium fluoride is the solute

water is the solvent

Question 2

Contrast the way ionic compounds dissolve in water with the way that polar covalent compounds in water.

Answer 2

(Ionic compounds split up into their ions when they dissolve) Ionic compounds will split up into 2 or more ions in a solution. Polar covalent compounds dissolve 1 molecule at a time.

Question 3

What is wrong with this statement: It does not matter what the solvent is in determining the solubility.

Answer 3

It does matter what the solvent is. The same solute will dissolve differently in different solvents.

Question 4

What is a saturated solution?

Answer 4

It is a solution that contains as much dissolved solute as is possible for the given temperature and pressure

Question 5

Within the topic of solution, what is precipitation?

Answer 5

It is the process by which a solid solute leaves a solution and turns back into its solid phase.

Question 6

What kind of solute dissolves best under high-temperature conditions?

Answer 6

Solid solutes dissolve best at high-temperature

Question 7

What kind of solute dissolves best under high-pressure conditions?

Answer 7

gas solutes dissolve best under high-pressure conditions

Question 8

What kind of solute has a solubility that is least affected by the conditions under which the solution is made?

Answer 8

liquid solutes are not effected strongly by the conditions of the solution.

Question 9

If a solid solute is not dissolving well in water, what can you do to increase its solubility?

Answer 9

you can increase the temperature to increase the solubility

Question 10

If a gas solute is not dissolving well in water, what can you do to increase its solubility?

Answer 10

decrease temperature and/or increase pressure

Question 11

If a chemist makes a solution in a beaker using water and a solute that dissolves endothermically in water, would you expect the beaker to feel hot or cold?

Answer 11

Cold

Question 12

What is the difference between molality and molarity?

Answer 12

molality takes the number of moles of solute and divides by the Kilograms of Solvent. molarity takes the number of moles of solute and divides by the Liters of the Solution.

Question 13

If you wanted to protect water from freezing which compound would accomplish this best: NaNO3, Mg(NO3)2, or Al(NO3)3?

Answer 13

Al(NO3)3. because it will split into the most ions

Question 14

What does the solubility of a solvent depend on?

Answer 14

The identity of the solute and the identity of the solvent

Question 15

What are the requirements for dissolving a solid?

Answer 15

the solvent molecules must be attracted to the solute molecules so strongly that the solvent molecules can get between the solute molecules or ions and pull them far apart from each other

Question 16

What are the requirements for dissolving a liquid?

Answer 16

The solvent molecules need to be attracted to the solute molecules only a small amount because the solvent does not need to separate the solute molecules very much. The solvent merely needs to get between the solute molecules.

Question 17

What are the requirements for dissolving a gas?

Answer 17

The solvent molecules must be attracted to the solute molecules enough to pull the solute molecules closer to one another.

Question 18

How does pressure effect each phase of solute?

Answer 18

If the pressure of a gas increases so does its solubility.

Pressure does not effect a solid or a liquid.

Question 19

How does temperature effect each phase of solute?

Answer 19

If the temp of a solid solute increases so does its solubility. if the temp of a gas solute decreases its solubility increases. the temp of a liquid doesn’t effect its solubility

Question 20

An open glass of soda pop sitting on the counter gets flatter than the same open glass of soda pop in the fridge. Why?

Answer 20

since the solubility of gases increases with decreasing temperature, a colder soda will hold onto more CO2 than a warm soda.

Question 21

If a solute dissolves in water endothermically, what can you do to decrease its solubility?

Answer 21

Decrease the temperature

Question 22

What is responsible for an ionic solid dissolving in water

Answer 22

The polar nature of water attracts the opposite ions in the solid and separates them.