1
Q
When does a physical change occur?
A
When the fundamental entities remain unchanged at the molecular level
2
Q
When does a chemical change occur?
A
When some kind of change in the chemical bonds occurs. A new substance is made
3
Q
What are the 4 evidences of a chemical change?
A
- Colour change
- Odour change
- State change
- Energy change
4
Q
What does the law of conservation of mass state?
A
The total mass of matter present after a chemical change is always the same as the total mass present before a chemical change
5
Q
What are the different types of reactions?
A
- Formation
- Decomposition
- Combustion
- Single replacement
- Double Replacement
6
Q
How can you tell a combustion reaction?
A
- They have CHO
- Their products are liquid water and something oxide
7
Q
What is it asking for when it says chemical amount?
A
How many mols
8
Q
What is the formula for calculating the number of mols?
A
n = m/M n = # of mols m = mass (g) M = Molar mass
