Photosynthesis, baking a cake, iron rust, cooked egg, rotten fruit, respiration, digestion
Examples of chemical changes
Change of matter in which the kind of matter stays the same. May change size, shape, texture or state, but particles have the same characteristics.
PHYSICAL CHANGE
Change of matter in which a NEW kind of matter is formed, many are non-reversible and forms a new substance
CHEMICAL CHANGE
Temperature at which a solid changes into a liquid
Melting point. Melting point of water is 0°C.
Why change of color is a sign of chemical change?
A fruit that turns brown is a sign of a chemical reaction
Liquid water + heat= water vapor. This is called
Evaporation
Temperature at which a liquid changes into a gas is called
Boiling point. The boiling point of water is 100 °C
Solid water + heat= liquid water. This is called
Melting
Changing water from one state to another, is a physical or chemical change?
Physical change, because particles that make up water do not change
Why formation of a solid is a sign of chemical change?
Formation of a solid is a sign of a chemical reaction.
Cutting paper, chopping wood, breaking glass, folding paper, cutting hair, melting ice, boiling water, crushing a can
Examples of physical changes
Name the three states of matter
SOLID, LIQUID AND GAS
Why production of odor is a sign of chemical change?
Bad odor in food means that food has undergone a chemical change.
The state of matter is determined by
the arrangement and movement of its particles
Characteristic of a substance that can only be observed by changing it into a different substance
Chemical property
Liquid water -heat= Solid water. This is called
Freezing
Temperature at which a liquid changes into a solid is called
Freezing point. The freezing point of water is 0° C.
Why formation of bubbles is a sign of chemical change?
Formation of bubbles are sign of a chemical reaction.
Why light and heat are signs of chemical change?
Light and heat are a sign of a chemical reaction.
Matter that has definite volume and shape, takes up space and particles are tightly packed, cannot be compressed
SOLID
Matter that has definite volume, takes the shape of its container, particles are close together but can move over and around each other, no compression
LIQUIDS
Matter that does NOT have a definite volume or shape, takes the shape of its container, particles are far apart, can be compressed and move quickly in all directions
GASES
Water vapor - heat= liquid water. This is called
Condensation
Temperature at which a gas changes into a liquid is called
Condensing point. The condensing point of water is 100°C.