krit.club logo

Materials and Matter - States of Matter (Solid, Liquid, Gas)

Grade 5IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

•

Matter is defined as anything that has mass and occupies space (VolumeVolume). It is composed of tiny particles called atoms and molecules.

•

The Kinetic Molecular Theory states that particles in all forms of matter are in constant motion. The amount of motion determines the state: SolidSolid, LiquidLiquid, or GasGas.

•

Solids have a definite shape and volume because particles are packed tightly in a fixed latticelattice structure and can only vibrate in place.

•

Liquids have a definite volume but no fixed shape; they take the shape of their container. Particles are close together but have enough energy to slide past one another.

•

Gases have no definite shape or volume. Particles move at high velocitiesvelocities and are far apart, meaning they can be compressed into a smaller VolumeVolume.

•

Phase changes occur when energy is added or removed. For example, adding heat to H2O(s)H_2O_{(s)} (ice) at 0∘C0^{\circ}C causes it to melt into H2O(l)H_2O_{(l)} (water).

•

The boiling point of water at sea level is 100∘C100^{\circ}C, where the liquid turns into H2O(g)H_2O_{(g)} (water vapor).

📐Formulae

Density=MassVolumeDensity = \frac{Mass}{Volume}

H2O(s)→MeltingH2O(l)H_2O_{(s)} \xrightarrow{Melting} H_2O_{(l)}

H2O(l)→EvaporationH2O(g)H_2O_{(l)} \xrightarrow{Evaporation} H_2O_{(g)}

Total Mass=Massparticle×Number of particlesTotal \, Mass = Mass_{particle} \times Number \, of \, particles

💡Examples

Problem 1:

If a sample of matter has a mass of 50g50\text{g} and occupies a volume of 10cm310\text{cm}^3, calculate its density.

Solution:

5g/cm35\text{g/cm}^3

Explanation:

Using the formula Density=mVDensity = \frac{m}{V}, we divide 50g50\text{g} by 10cm310\text{cm}^3 to get 5g/cm35\text{g/cm}^3.

Problem 2:

Explain why a gas can be compressed into a 1L1\text{L} cylinder even if its original volume was 5L5\text{L}.

Solution:

Gas particles have large spaces between them (d≫particle diameterd \gg \text{particle diameter}).

Explanation:

Because gas particles are far apart and have weak intermolecular forces, they can be pushed closer together when pressure is applied, reducing the total VolumeVolume.

Problem 3:

What process is occurring when water droplets form on the outside of a cold glass of lemonade?

Solution:

CondensationCondensation

Explanation:

Water vapor (H2O(g)H_2O_{(g)}) in the air loses thermal energy when it touches the cold surface, slowing down the particles until they form a liquid (H2O(l)H_2O_{(l)}).