Science Grade 7: Solutions

Question 1

What is a solution?

Answer 1

A solution is a homogeneous mixture of two or more substances in which the dissolved particles are too small to be seen or to settle out of the mixture.

Question 2

What are the two parts of a solution?

Answer 2

In a solution, the substance that dissolves is the solute, and the substance that dissolves the solute is the solvent.

Question 3

What is an example of a substance that is soluble in water and a substance that is insoluble in water?

Answer 3

Soluble in water: Salt (NaCl)

Insoluble in water: Oil

Question 4

What is the state of matter of solutions?

Answer 4

Solutions may be liquids such as salt water, solids such as alloys, or gases such as air.

Question 5

Is a solution homogeneous or heterogeneous?

Answer 5

A solution is homogeneous

Question 6

What is the difference between homogeneous and heterogeneous?

Answer 6

Homogeneous - The solute is fully dissolved in the solvent, meaning that the atoms of the solute are equally distributed in the solvent
Heterogeneous - The atoms of the solute are not evenly spaced in the solvent, so the solute is still visible.

Question 7

What are some factors that affect the rate at which a solute dissolves in a solvent?

Answer 7

Dissolve faster when:

• Solvent and solute are stirred
• Solvent is warmer
• Solute consists of smaller particles with more surface area

Question 8

What is freezing point depression?

Answer 8

A solute generally lowers the freezing point of a solvent, which is called freezing point depression. For example, spreading salt on an icy road melts the ice.

Question 9

What is boiling point elevation?

Answer 9

A solute generally raises the boiling point of a solvent, which is called boiling point elevation. For example, adding antifreeze to the water in a car radiator prevents the water from boiling.

Question 10

What is solubility?

Answer 10

Solubility is the amount of solute that can dissolve in a given amount of solvent at a given temperature.

Question 11

What factors affect solubility?

Answer 11

• The combination of which exact solvent and solute (obviously)
• Temperature
• Pressure (for solubility of gases)

Question 12

What is the difference between saturated and unsaturated solutions?

Answer 12

A saturated solution is a solution that contains as much solute as can dissolve in a given solvent at a given temperature. An unsaturated solution is a solution that contains less solute than can dissolve in a given solvent at a given temperature