Question

1. what are 2 examples of chemical change? 6. fill in the blank: all chemical changes are accompanied by a 7. fill in the chart: write physical change and chemical change for the following scenarios.

Explanation:

1. Chemical changes involve the formation of new substances. Examples include rusting of iron (iron reacts with oxygen and moisture to form iron - oxide) and burning of wood (wood reacts with oxygen to produce carbon - dioxide, water vapor, etc.).
2. Chemical changes are often accompanied by energy changes (such as heat, light, or electricity being released or absorbed), color changes, gas evolution, or precipitation formation.
3. Physical changes do not change the chemical composition of a substance. Examples are melting of ice (solid water changes to liquid water), and dissolving salt in water (salt can be recovered by evaporation). Chemical changes form new substances. For example, when hydrogen and oxygen combine to form water, it is a chemical change.

Answer:

1. Rusting of iron, burning of wood
2. Energy changes, color changes, gas evolution, precipitation formation
3. Physical change: Melting of ice; Chemical change: Hydrogen and oxygen combining to form water