(1.1-1.7C) States of Matter, Diffusion + Solubility

What are the 3 states of matter?

Solid, Liquid, Gas

Describe the characteristics of a solid.

Particles:

Regular arrangement

Vibrate about a fixed point

Close together- all touching

Describe the characteristics of a liquid.

Particles:

Random arrangement

Slide around each other

Close together

Describe the characteristics of a gas.

Particles:

Randomly arranged

Moving quickly in random directions

Far apart

How does a substance change state from solid to liquid/liquid to gas?

Energy is needed to overcome the bonds between the particles.

The stronger the bonds, the more energy needed.

Describe a solid→liquid change.

Melting

• thermal energy absorbed by particles

• transformed to kinetic energy

• makes particles vibrate more + flow

Describe a liquid→gas change.

Boiling

• thermal energy causes bubbles of gas inside the liquid

• liquid particles escape from surface/within liquid

• happens at a specific temperature

Evaporation

• occurs over a range of temperatures

• only occurs at the surface where particles w. high energy can escape

• greater surface area, warmer the surface = faster evaporation

Describe a liquid→solid change.

Freezing

• significant decrease in temperature

• occurs at a specific temperature

Describe a gas→liquid change.

Condensation

• occurs over a range of temperatures

• when a gas is cooled, the particles lose energy

• lack energy to bounce away after colliding

• grouping together into a liquid

Describe a solid→gas change.

Sublimation

• only happens to specific solids- like iodine or solid CO2

• reverse- desublimation/deposition

What is diffusion?

The net movement of particles from an area of high concentration to an area of low concentration.

Give an example of diffusion in gases. Explain.

Bromine gas in a jar:

after 2 minutes, it has diffused from one region to throughout the jar.

• Air particles and bromine particles can easily mix due to random movements with gaps between particles.

Give an example of diffusion in liquids. Explain.

Potassium manganate (VII) crystals in water:

• produce a purple solution

  • water and potassium manganate solution move randomly

  • particles can mix together

  • slower than in gases as particles are closer together + move slower

Give an example of dilution in liquids. Explain.

Potassium manganate (VII) crystals in water:

• The resultant solution can be diluted multiple times

• colour fades but does not disappear easily

  • indicates- lots of particles in a small amount of crystals

  • small particles

Define solute.

The substance that dissolves.

Define a solvent.

The liquid in which a solute dissolves

Define soluution

Mixture formed when a solute + solvent mix

Define soluble

Describes a substance which will dissolve

Define insoluble

Describes a substance which will not dissolve

Define saturated solution

A solution with the maximum concentration of solute dissolved in the solvent

How is the solubility of a substance recorded?

solubility per 100g of solvent

What factors affect the solubility of gases?

more pressure = more soluble

more temperature = less soluble

What is a solubility curve?

solubility in g per 100 g of water against temperature

• records the maximum solubility of a substance at different temperatures

Describe how to investigate the solubility of a solid in water at a specific temperature.

1. Two beakers- one in hot bath and other in ice bath

2. 4cm³ of distilled water in a boiling tube

3. Add 2.6g of ammonium chloride

4. Place into hot beaker and dissolve

5. Move to ice beaker and let cool

6. Record temperature at which crystals appear

7. Add 1cm³ water and heat again

8. Repeat until 10cm³ has been added.