When two substances react to form products, the reactant which is used up is called the
a. limiting reagent
b. determining reagent
c. excess reagent
d. catalytic reagent?

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?