Chem Notes Ch 4

Question 1

Avogadro’s number

Answer 1

Equals the number of atoms in 12 grams of the pure isotope Carbon-12, which is 6.022 x 10^(23) mol^(-1)

Question 2

mol equation

Answer 2

mol = mass (g)/ molar mass (g/mol)

Question 3

density equation

Answer 3

density = mass (g) / volume (mL)

Under constant temperature and pressure, the density of a pure substance also remains
constant.

Question 4

Empirical formula

Answer 4

Formula of a compound with the lowest whole number ratio

Question 5

Molecular formula

Answer 5

A multiple of the empirical formula, gives the true number of atoms in the molecule

Question 6

Percent composition

Answer 6

Percent of the compound’s mass that is made up by that element

(Mass of element in formula (g) / molar mass of compound (g/mol)) * 100%

Question 7

Limiting reagent

Answer 7

The reactant that determines how much product is formed

Question 8

Theoretical yield

Answer 8

Maximum amount of product that one can expect to obtain from a chemical reaction

Question 9

Percent yield

Answer 9

(actual yield/theoretical yield)*100%