Answer:
Explanation:
A group of two or more smaller molecules is the correct answer
Molar Mass of Calcium carbonate:-








Now



Answer:
This is very easy Cuz We have 2Na2O We have O2 so thats molecule of Oxygen and its same on product We need to balance Na on start We have 1 on product We have 2 so Just put 2 at start....
Explanation:
Sorry for bad english not my first language :(
2Na+O2-->2Na20