Solutions Pre-Test

What is the solubility of 55g of Sodium Nitrate (NaNO3) dissolved in 100g of water at 35 degrees Celsius?

• unsaturated

• saturated

• supersaturated

• insoluble

Answer explanation

At 35 degrees Celsius, 55g of Sodium Nitrate dissolved in 100g of water is unsaturated because when you look at the solubility curve, that point is under the line.

A solution containing 90g of HCl in 100g of water at at 10 degrees Celsius would be described as-

• insoluble

• unsaturated

• saturated

• supersaturated

Answer explanation

At 10 degrees Celsius, 90g of HCl dissolved in 100g of water is supersaturated because when you look at the solubility curve, that point is above the line.

A solution containing 80g of Potassium Nitrate (KNO3) in 100g of water at at 60 degrees Celsius would be described as-

• supersaturated

• unsaturated

• insoluble

• saturated

Answer explanation

At 60 degrees Celsius, 80g of Potassium Nitrate dissolved in 100g of water is unsaturated because when you look at the solubility curve, that point is below the line.

At what temperature would 50g of Potassium Nitrate (KNO3) in 100g of water make a saturated solution?

• 60 degrees Celsius

• 30 degrees Celsius

• 42 degrees Celsius

• 50 degrees Celsius

Answer explanation

At 30 degrees Celsius, 50g of Potassium Nitrate dissolved in 100g of water is saturated because the point is on the line.

Which of the following affect the rate at which a solid dissolves in water? (select ALL that apply)

• Heating up the water

• Agitation or Stirring

• The size of the solid

• Increasing the pressure

Answer explanation

Increasing the pressure only increases the rate at which GASES dissolve, not solids.

Answer explanation

Looking at the Solubility rules to the left, Cl is soluble in water UNLESS it forms a compound with Ag.

Water is described as being a universal solvent because it is

• massive

• nonpolar

• clear

• polar

Answer explanation

Water molecules are polar. They have a bent shape giving it partial charges to each end. The hydrogen atom is partially positive and the oxygen end partially negative.

If something dissolves in water it is said to be-

• massive

• polar

• nonpolar

• large

Answer explanation

If a substance dissolves in water, it is said to be polar because of the rule "like dissolves like" meaning polar substances only dissolve other polar substances.

Oil can dissolve in water

• True

• False

Answer explanation

Oil does not dissolve in water because it is nonpolar. The only substances that dissolve in water will be other polar substances because "like dissolves like"

In our Borax Lab, we dissolved borax in a cup of hot water. What was the solute?

• Water

• Water and Borax

• Borax

• Food Coloring

Answer explanation

The solute is the substance that is dissolved.