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States of Matter

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3. Changes in Matter

1. What is Matter?

2. States of Matter

These processes happen at ANY temperatures

These processes happen at SPECIFIC temperatures

Freezing

Condensation

Melting

Boiling

Evaporation

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Heat is Lost

Heat is Gained

Processes of Changes in State

How do I know if freezing or melting is taking place? Ask yourself the following:

• What is the change in state?
• Is it a heat gain or a heat loss process?

Freezing and melting of water both take place at only 0°C, but freezing is a heat loss process where liquid loses heat to form solid, while melting is a heat gain process where solid gains heat to form liquid!

WAIT! Doesn't ice also melt at 0°C? (or does it freeze?)

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• No fixed volume
• No fixed shape

• Fixed volume
• No fixed shape

• Fixed volume
• Fixed shape

gas

liquid

solid

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STATES OF MATTER

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has mass

volume

Matter is anything that and

What is Matter?

Volume is the space something occupies. Volume of liquids can be measured using a cylinder.Volumes of solids can be measured by measuring and calculating the volume. Volume is usually measured in cubic centimeters or liters.

What does volume mean?

Every liquid can boil, but different liquids boil at different temperatures. For example, water only boils at 100°C while iron only boils at 2862°C!

Boiling

is a process where liquid gains heat and changes to gas, at a fixed temperature.

• Water boils at 100°C.
• This means that only at 100°C will water change into water vapour through the process of boiling.
• During boiling, temperature of the boiling water will remain at 100°C until all water is changed to water vapour.
• Evaporation will also be taking place since it can take place at all temperatures, but the main process at 100°C for water is boiling.

• The atoms in solids are held close together
• The atoms in liquids are held very loosely, so they move around
• The atoms in gas are not held together, so they move a lot

Condensation can take place at any temperature, as long as there is a temperature difference, giving rise to heat flow (heat loss of the gas)

Condensation

is a process where gas loses heat and changes to liquid, at any temperature.

Process of condensation causing the formation of water droplets on the surface: Warmer water vapour in the surrounding air touches the cooler surface of the glass. Warmer water vapour loses heat and condenses, turning into liquid (water droplets). Process of condensation causing the formation of mist: Warmer water vapour (steam) from the kettle touches the cooler surrounding air. Warmer water vapour loses heat and condenses, turning into liquid (mist).

The mass of matter can be measured using various apparatus like electronic balance and weighing balance. Mass is usually measured in grams or kilograms. It is very similar to weight.

What is mass?

Wait! Doesn't melting happen at 0°C?

Every liquid can freeze, but different liquids freeze at different temperatures. For example, ice only freezes at 0°C!

Freezing

is a process where liquid loses heat and changes to solid, at a fixed temperature

• Water freezes at 0°C.
• This means that only at 0°C will water change into ice through the process of freezing.
• During freezing, temperature of the freezing water will remain at 0°C until all water is changed to ice.

Relationships to take note:

• When there is a presence of wind, rate of evaporation increases.
• When the exposed surface area increases, rate of evaporation increases.
• When the temperature of the liquid / the surroundings increases, rate of evaporation increases

Evaporation can take place at any temperature, as long as there is a temperature difference, giving rise to heat flow (heat gain of the liquid).

Evaporation

is a process where liquid gains heat and changes to gas, at any temperature.

The rate of evaporation depends on: Wind Exposed surface area Temperature

Every solid can melt, but different solids melt at different temperatures. For example, ice only melts at 0°C while glass melts at about 1600°C!

Wait! Doesn't freezing happen at 0°C?

Melting

is a process where solid gains heat and changes to liquid, at a fixed temperature.

• Ice melts at 0°C.
• This means that only at 0°C will ice change into water through the process of melting.
• During melting, temperature of the melting ice will remain at 0°C until all ice is changed to water.
• Evaporation will also be taking place since it can take place at all temperatures, but the main process at 0°C for water is melting.