Chapter 3 Concepts

Question 1

molecular weight

Answer 1

the sum of the atomic weights of the atoms in a molecule (same thing as a formula weight, but referred to as molecular weight when the chemical formula is for a molecule)

Question 2

formula weight

Answer 2

the sum of the atomic weights for the atoms in a chemical formula (generally reported for ionic compounds)

Question 3

percent composition (how to find mass percent of an element in a given formula)

Answer 3

(number of atoms)(atomic weight)
—————————————————- x 100 = % element
(FW of the compound)

Question 4

what is a Mole

Answer 4

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Question 5

Avogadro’s number

Answer 5

6.02 x 10^23

Question 6

how to use Avogadro’s number to find # of atoms, molecules or formula units

Answer 6

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Question 7

how to find Molar mass

Answer 7

• The molar mass of an element is the mass number for the element that we find on the periodic table.
• The formula weight (in amu’s) will be the same number as the molar mass (in g/mol).

Question 8

how to convert grams to moles

Answer 8

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Question 9

how to convert grams to mol and to #units (atoms, molecules etc)

Answer 9

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Question 10

find Empirical formula

-from masses of elements

Answer 10

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Question 11

find Empirical formula

-from % composition

Answer 11

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Question 12

find Molecular Formula

-from empirical formula

Answer 12

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Question 13

find Molecular Formula

-from % composition & Mol. Wt

Answer 13

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Question 14

how to use Combustion Analysis to find % of elements

Answer 14

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Question 15

how to convert g to mol

Answer 15

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Question 16

How to convert mol to g

Answer 16

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Question 17

how to find limiting reactant if masses of both the reactants is given

Answer 17

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Question 18

how to find theoretical yield

Answer 18

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Question 19

how to find % yield

Answer 19

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Question 20

difference between theoretical and % yield

Answer 20

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Question 21

definition of molar mass

Answer 21

the mass of 1 mol of a substance (i.e., g/mol).