Chemistry- Moles

Question 1

mole

Answer 1

SI unit of quantity, also know as Avogrado’s number (number of atoms in 12.01 grams of carbon)

Question 2

atomic mass

Answer 2

weighted average of the masses of all the isotopes in amu

Question 3

gram atomic mas (GAM)

Answer 3

atomic mass in grams unit

Question 4

formula mass

Answer 4

mass of the one formula unit of a compound in amu

Question 5

gram formula mass (GFM)

Answer 5

formula mass in grams unit

Question 6

molecular mass

Answer 6

mass of one molecule in amu

Question 7

gram molecular mass (GMM)

Answer 7

molecular mass in grams unit

Question 8

molar mass

Answer 8

• atomic mass expressed in grams (g/mol)

- molar mass of a substance is the sum of the molar masses of each element

Question 9

mole and molecule

Answer 9

1 mole of a substance is 6.02 x 10^23 molecules of that substance

Question 10

mole and mass of a substance

Answer 10

1 mole of a substance that has a mass in grams numerically equal to its formula/molecular mass

Question 11

mole and volume of gas at STP

Answer 11

1 mole of any gas occupies the volume of 22.4 L at STP

Question 12

mole and liquids

Answer 12

must know density

Question 13

percent composition

Answer 13

(mass contributed by the element / molar mass of compound) * 100

Question 14

hydrates

Answer 14

• compounds containing water molecules combines in a definite ratio as part of the crystal structure
• (mass of water / molar mass of compound) * 100

Question 15

empirical formula

Answer 15

• provides the ratio of atoms of each element in a compound in lowest terms
• CH2O

Question 16

molecular formula

Answer 16

• provides the actual # of atoms of each element in a compound
• C6H12O6 (glucose)

Question 17

structural formula

Answer 17

represents how the individual atoms are arranged in relation to one another

Question 18

find empirical formula

Answer 18

1. find mole of each element
2. divide each mole by the smallest #
3. multiply if needed (subscripts have to be whole numbers)

Question 19

find molecular formula from empirical formula

Answer 19

• need molar mass
• (molar mass / empirical formula mass) = coefficient
• (coefficient)(empirical formula) = molecular formula

Question 20

stoichiometry

Answer 20

the study of the quantitative aspects of chemical reactions

Question 21

Mole to Mole Conversion

Answer 21

• coefficients represent ratio of moles
• as the number of moles of one substance changes, the moles of all the other substances will change proportionally
• MUST BALANCE EQUATION FIRST

Question 22

Mass to Mass Conversion

Answer 22

mass given –> moles given –> moles required –> mass required

Question 23

Mass to Volume Conversion

Answer 23

mass given –> moles given –> moles required –> volume required

Question 24

Volume to Volume Conversion

Answer 24

volume given –> moles given –> moles required –> volume required

Question 25

limiting reactant

Answer 25

the reactant that runs out first in a reaction, limits the amount of product formed

Question 26

excess reactant

Answer 26

reactant that will be left over at the completion of the reaction

Question 27

theoretical yield

Answer 27

- amount of products that are produced if the reaction goes to completion - calculated

Question 28

percent yield

Answer 28

- provides a means of evaluating how effective a reaction was - % yield = (actual / theoretical) * 100 - measured

Question 29

not all reactions give 100% yield due to

Answer 29

- impurities - unwanted by-products - leakage - reaction does not reach completion