Unit 10 Water

Unit 10 Water and Solutions

You will need a calculator, solubility rules chart and solubility curves graph.

Describe the unique role of water in solutions in terms of polarity.

• Water is polar (positive hydrogen atoms, negative oxygen atom).

• water is the universal solvent and dissolves other polar molecules.

Multiple Choice

Which of these molecules represents water with the correct charges?

Multiple Choice

Water is polar and considered a universal solvent, oil does not dissolve in water so it must be..

• polar

• non-polar

• universal solvent

• no idea

Multiple Choice

Water is polar and considered a universal solvent, which of these is NOT soluble in water?

• Sugar

• Salt

• Bacon Grease

• Lemon Juice

Solubility Rules

You should be able to determine if a substance is soluble or insoluble in water.

You should also be able to identify a precipitation reaction.

Multiple Choice

Is CaBr₂ soluble or insoluble?

• Soluble

• Insoluble

Multiple Choice

Is HgI₂ soluble or insoluble?

• Soluble

• Insoluble

Multiple Choice

Is Ca(OH)₂ soluble or insoluble?

• Soluble

• Insoluble

A precipitation reaction happens when two dissolved substances in water mix together and form an insoluble solid that sinks to the bottom. That solid is called a precipitate.

Multiple Choice

Does this reaction form a precipitate?

• Yes, because of BaSO4

• Yes, because of NaCl

• No

• Yes, because of BaCl2

Molarity Calculations

Used to calculate the concentration of a solution.

Multiple Choice

M1 = 5M

V1 = 10L

M2 = 10M

V2= ?

• 5L

• 10L

• 15L

• 20L

Distinguish among unsaturated, saturated and supersaturated solutions.

Multiple Choice

Which type of solution has less than the maximum amount of solute dissolved in it?

• Unsaturated

• Saturated

• Supersaturated

Multiple Choice

How much KClO3 would dissolve at 30^oC in 100 ml of water?

• 10

• 20

• 65

• 100

Multiple Choice

How much NaNO3 would dissolve at 30^oC in 100 ml of water?

• 10

• 20

• 95

• 100

Multiple Choice

How solution of NaCl contains 60 grams of solute dissolved in 100 ml of water. At 50 degrees Celsius this solution would be classified as...

• unsaturated

• saturated

• supersaturated

Multiple Choice

How much NaCl would dissolve at 30^oC in 100 ml of water?

• 20

• 38

• 95

• 50

Multiple Choice

In which scenario would a saturated solution become unsaturated?

• adding more sugar

• heating up the solution

• adding a seed crystal

• mixing it more

Multiple Choice

What type of solution is made by heating it up, dissolving more solvent, and then cooling it back down?

• Unsaturated Solution

• Saturated Solution

• Supersaturated Solution

Factors affecting the solubility of a solid in water...

• Increase temperature

• Increase surface area of solute

• Agitation

Multiple Choice

Which of the following is NOT a way to increase the solubility of a solid?

• Heating it up

• Put it in the fridge

• Crush the solid into small pieces

• Stir the mixture

Multiple Choice

Which type of solute will dissolve quickest?

• A

• B

• C

Multiple Choice

Which temperature would allow more solid solute to dissolve in water?

• 20 Degrees Celsius

• 50 Degrees Celsius

• 5 Degrees Celsius

• 100 Degrees Celsius