Answer:
combustion is a high-temperature exothermic redox chemical reaction between a fuel and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke.
The answer for it is C. when you mix it with water it fizzes
Answer: 
Explanation:
25.3% Mg
74.7% Cl
First step: change % to g
25.3g Mg
74.7g Cl
Second step: calculate g/mol of each compound. You can do this by using the atomic mass.


Third step: determine the lowest number and divide everything by it. Of the result, extract whole number only.


Fourth step: Write each compound with their respective number below.
This empirical formula should be: 