Properties of Water and Solutions

Water Properties 6.6a-c

Solutions

A solution is a solvent + solute. The solute + solvent is evenly mixed/uniform throughout the solution. It is completely dissolved. There is no chemical change taking place.

Multiple Select

Which statements correctly define a solution?

• The solute particles are completely dissolved in a solution.

• The solute particles in a solution settle down if left undisturbed.

• It does not change the chemical composition of the dissolved substances.

• It does not change the chemical composition of the dissolved substances.

Solutions

In a solution, the solute is dissolved in a solvent. For example, salt (solute) and water (solvent). Water is the universal solvent and will always be the solvent in a solution.

Multiple Select

A girl is making lemonade. She dissolves 2 tablespoons of sugar, 3 tablespoons of lemon juice, and a half tablespoon of salt in 2 cups of water. Which option correctly classifies the substances?

• Salt - solute

• Lemon juice - solvent

• Lemonade - solvent

• Sugar - solute

• Water - solvent

Multiple Choice

The substance which dissolves in a solution is known as a

• Dilute

• Solute

• Filtrate

• Solvent

Adhesion

Adhesion is the sticking together of unlike materials. It is what causes water to stick on glass and other surfaces.

Adhesion causes capillary action, which is the movement upward of water like a train. An example of capillary action is a plant sucking up water through its roots.

Multiple Choice

Capillary action is the process of water molecules moving upwards through a narrow tube, such as a plant steam. What characteristic of water causes this process?

• Surface tension

• Hydrogen bonds

• Adhesion

• Surface tension

Surface tension

The tightness across the surface of water that is caused by polar molecules pulling on each other is called surface tension.

Water acts like an elastic sheet, resisting tearing. Examples include paperclips on water or insects walking on water.

Multiple Choice

The tightness across the surface of water that is caused by polar molecules pulling on each other is called--

• condensation

• capillary action

• surface tension

• universal solvent

Multiple Choice

All of the following are examples of surface tension EXCEPT —

• raindrops forming round beads when they fall on a car windshield

• athletic clothing that allows you to keep cool

• an insect “walking” on water

• dropping  paper clips into a full glass of water

Water states

There are three states of water. Solid (ice), liquid (water), gas (water vapor). Water freezes at 30^oCelsius and boils at 100^oCelsius. The process of going from liquid to solid is freezing, the process of going from liquid to gas is evaporation. The process of going from gas to liquid is condensation.

Properties of Water

Water is a polar molecule. It has a high boiling point, floats when it freezes, and has high surface tension.

Multiple Choice

What occurs when water reaches 100°C?

• It has reached the right temperature to be able to dissolve a solute.

• Vapor pressure allows bubbles to form inside the body of the liquid, causing it to boil.

• This is known as superheating and can only be achieved in laboratory conditions.

• It sublimes, meaning it changes directly from solid form to vapor.