Question

1. why is denting the bike fender not a chemical change?

a. the bike looks different
b. the metal does not change into another substance it only changed its shape
c. the metal does not change its shape it changed into another substance
d. the bike fell apart

1. how can we tell if a chemical change has taken place?

a. you can’t tell
b. a new substance is formed that is the same as the old substance
c. a new substance is formed that is different from the original substance
d. it only changes shape

1. why did dad tell alexis and javar to clean and dry the bikes?

a. so their bikes would not rust
b. so their bikes would be ready to ride again
c. dad does not like dirty bikes

Explanation:

1. A chemical change involves the formation of a new substance. Denting a bike fender only changes the shape of the metal (a physical change), not its chemical composition.
2. The key indicator of a chemical change is the formation of a new substance that is different from the original.
3. Cleaning and drying bikes helps prevent rust (a chemical reaction between metal, water, and oxygen).

Answer:

1. B. The metal does not change into another substance it only changed its shape
2. C. A new substance is formed that is different from the original substance
3. A. So their bikes would not rust