4.3: Conservation of Mass and Chemical Equations

Question 1

chemical change

Answer 1

the conversion of reactants into products. the products have different chemical properties than the reactants

Question 2

the law of conservation of mass

Answer 2

Antoine Lavoisier

in a chemical reaction, the total mass of the products is always the same as the total mass of the reactants

Question 3

how did Lavoisier’s work aid Dalton?

Answer 3

it allowed Dalton to re-introduce his atomic theory to the world, suggesting that each atom in the reactants was also present in the products

Question 4

three types of equations

Answer 4

word equation
skeleton equation
balanced chemical equation

Question 5

abbreviations for the state of a substance

Answer 5

(s) (l) (g) (aq)

Question 6

outline one practical use of the law of conservation of mass

Answer 6

sometimes, a toxic chemical is cleaned up by adding another chemical. Care must be taken to ensure that the exact amount of chemical needed is used to clean up all of the toxic chemical. Otherwise, there will be excess, which may harm the environment.

industrial chemistry requires knowledge of conservation of mass so that they will not waste expensive chemicals. In addition, excess chemicals will have to be discarded, which (if done properly) is a lengthy process

Question 7

tips for balancing

Answer 7

balance compounds first, elements after, and H or O last