Chemical Reactions Flashcards
1
Q
What are chemical reactions
A
They are a change in atoms which are rearranged to create new substances. The atoms are joined together in the reaction
2
Q
Two chemical reactions
A
Make new substances
Transfer energy to or from the surroundings
3
Q
Is a chemical reaction reversible
A
no
4
Q
How do you know if it is a chemical reaction
A
- see huge flames or tiny sparks
- notice a sweet smell or a foul stink
- feel the chemicals getting warmer or colder
- hearing a loud bang or gentle fizzing
5
Q
Why are chemical reactions useful
A
They make many new substances such as
- medicines
- fabric such as polyester
- building materials such as cement
6
Q
Are all chemical reactions fast?
A
Scientists usually try to speed up the pace which is called catalysts to speed up slow reactions.
