stoichiometry

Question 1

what is a mole

Answer 1

unit of measurement for an amount of a chemical substance

Question 2

what is Avogadro’s number?

Answer 2

6.022 x 10^23

Question 3

what is a chemical equation?

Answer 3

describes proportions of reactants to products during a chemical reaction

Question 4

what is a reactant?

Answer 4

substance consumed

Question 5

what is a product?

Answer 5

substance formed

Question 6

what does the law of conservation of mass state?

Answer 6

the sum of the masses of the reactants in a chemical equation is equal to the sum of the masses of the products of the reactants

Question 7

what is stoichiometry

Answer 7

a quantitative relation between reactants and products in a chemical equation

Question 8

what are the guidelines for balancing chemical equations?

Answer 8

-before placing coefficients in an equation, check that the formulas are correct
-never change the subscripts in a chemical formula to balance the equation
-balance each element in the equation starting with the most complex formula
-balance polyatomic ions as a single unit if it appears on both sides of the equation
-the coefficients must be whole numbers

Question 9

what is the formula for a combustion reaction?

Answer 9

CxHy+O2 –> CO2+H2O

Question 10

what is the formula for an incomplete combustion reaction?

Answer 10

CxHy+O2 –> CO+H2O

Question 11

what is a limiting reactant?

Answer 11

reactant that controls the amount of product you can make

Question 12

what are the steps to solving a limiting reactant problem?

Answer 12

1. calculate the mass of the product that can be produced from the first reactant
2. calculate the mass of the product that can be produced from the second reactant
3. the limiting reactant is the reactant that produces the least amount of product

Question 13

what is actual yield?

Answer 13

the amount of product collected when you perform an experiment

Question 14

what is theoretical yield?

Answer 14

amount of product calculated from a limiting reactant problem

Question 15

what is the formula for percent yield?

Answer 15

(actual yield/theoretical yield)*100

Question 16

what is percentage composition?

Answer 16

mass percentage of each element in the compound

Question 17

what are the steps for determining percentage composition?

Answer 17

1. assume you have 1 mole of the compound
2. determine the molecular mass of the compound
3. find the composition of the compound by comparing the masses of each element to the molar mass of the compound

Question 18

what is an empirical formula?

Answer 18

simplest whole number mole ratio of ions in a formula unit or atoms of each element in a molecule