chemistry quiz #2 - physical and chemical pro...\nwater reacts with sodium metal\na solid is crushed into a…
chemistry quiz #2 - physical and chemical pro...\nwater reacts with sodium metal\na solid is crushed into a powder.\nmixing salt and pepper\ntwo chemicals are mixed together and a gas is produced.\nan ice cube is placed in the sun. later there is a puddle of water. later the puddle is gone.\na marshmallow is cut in half\ntwo substances are mixed and light is produced.\na bicycle changes colour as it rusts.\nchocolate syrup is dissolved in milk\na marshmallow is toasted over a campfire\n1. physical change\n2. chemical change
Answer
Brief Explanations:
- Water reacting with sodium metal forms new substances (sodium hydroxide and hydrogen), so it's a chemical change.
- Crushing a solid into powder only changes the physical form, not the substance itself, so it's a physical change.
- Mixing salt and pepper is just a physical combination without forming new substances, so it's a physical change.
- Two chemicals reacting to produce a gas means new substances are formed, so it's a chemical change.
- Ice - cube melting and then evaporating are physical state changes without new substances, so it's a physical change.
- Cutting a marshmallow in half only changes its physical shape, so it's a physical change.
- Two substances producing light likely means a chemical reaction is occurring, so it's a chemical change.
- A bicycle rusting is a chemical reaction between iron in the bicycle and oxygen in the air, so it's a chemical change.
- Dissolving chocolate syrup in milk is a physical process of mixing without new chemical substances formed, so it's a physical change.
- Toasting a marshmallow over a camp - fire causes a chemical reaction due to heat, so it's a chemical change.
Answer:
- Water reacts with sodium metal: 2. Chemical Change
- A solid is crushed into a powder: 1. Physical Change
- Mixing salt and pepper: 1. Physical Change
- Two chemicals are mixed together and a gas is produced: 2. Chemical Change
- An ice cube is placed in the sun. Later there is a puddle of water. Later the puddle is gone: 1. Physical Change
- A marshmallow is cut in half: 1. Physical Change
- Two substances are mixed and light is produced: 2. Chemical Change
- A bicycle changes colour as it rusts: 2. Chemical Change
- Chocolate syrup is dissolved in milk: 1. Physical Change
- A marshmallow is toasted over a campfire: 2. Chemical Change