It went under a physical change because it (1) changed color. (2) changed form.
Answer:
B 1,3
Explanation:
Count the atoms on each side of the arrow, they have to be equal
After arrow
2x C
6x O
4x H
Before the arrow
2x C - correct, as it is the only compound with C then there must only be 1 mole of it.
This is also the correct amount of H
We need 6x O total so 6/2 = 3
So there are 3 moles of O
The mass of magnesium should be less than 0.09g to enable a faster reaction rate. Magnesium reacts to form a white coating around it which stops the reaction. The lesser the gram the faster the reaction before the coating is formed. It is also advisable to use magnesium fillings to increase the rate of reaction.