What is a coefficient?

A coefficient is the larger number in a chemical equation. For example, 2H2o, the larger number,2 , in the equation, which is before the H, is the coefficient. It tells us how many molecules of the substance there is.

What is a subscript?

A subscript is the smaller number in the chemical equation. For example, H2o, the number 2 in the equation is the subscript. It tells us how many atoms of each element is present in the equation. 

What is a chemical equation?

A chemical equation is the symbolic representation of a chemical reaction where in the reactant entities are given on the left hand side and the product entities on the right hand side.

Experiment 2 ( CH3COOH + NaHCO3 ---> CHCOONa +H2O + CO2 )

What was a chemical reaction in expeeriment 2?
 
  We poured 20 ml of vinegar into a 100 ml  measuring tube. Next, we lighted a tea candle and placed it into a plastic contanier bowl. The candled's depth is approximately 100 ml. Then we added about 1 gram of baking soda and held the measuring tube oveer the contanier bowl and the gas created, and took out the fire on the candle.

Experiment 1 (CH3COOH + NaHCO3 ---> CH3COONa + H2O + CO2)

What chemical reaction occured in experiment 1?

 We poured 10 ml. of vinegar into a test tube ( approximately 57 ml ). Then, we added approximately 0.5 g. of baking soda (sodium bircarbonate). When the two substances were combined it created foam, afterwards, it transformed into a gas, carbon dioxide(CO2), which blew up the balloon.

Chemical reaction (definition)

A chemical reaction is the process that involves the rearrangement of molecules or ionic structure of a substance,  a change in physical form or a nuclear reaction is the opposite.

Law of Conservation of Mass

Law of Conservation of Mass means that mass cannot be created or destroyed by ordinary chemical or physical changes. So even though you make a new substance you will not be able to destroy or create the mass(es) of the element(s).