Moles and Molar Mass

Moles

100

How many things are in one mole?

6.02 X 10²³

200

Who is the scientist that "discovered" the mole?

Avogadro

300

How would you convert from atoms to moles?

Divide by Avogadro's number.

400

5.67 x 10²⁴ atoms of copper = ________ moles of copper

9.42 moles

500

How would you convert from moles to atoms?

Multiply by Avogadro's.

Molar Mass

100

CaCl₂

110.98 g/mol

200

What is the proper unit for molar mass?

grams/mol

300

Iron (II) Chloride

126.75 grams/mol

400

C₁₂H₂₂O₁₁

342.29 grams/mol

500

Ammonium chloride

53.49 grams/mole

% Composition

100

Write out the formula for finding % composition

(mass of element/mass of whole compound) x 100

200

I make a glass of salt water using 34 grams of salt and 150 grams of water. What is the % by mass of salt in the solution?

22.67 %

300

I have 50 grams of 23% salt water solution. How much salt is in the solution?

11.5 grams salt

400

Find the percent composition of NaCl

60.7% chlorine, 39.3 % sodium

Empirical Formula

100

How would you define empirical formula?

Simplest whole number ratio

200

Find the empirical formula of C₆H₁₂O₆

CH₂O

300

An iron oxide compound is composed of 75.4 g iron and 37.88 g oxygen.  Find the empirical formula.

FeO₂

400

Write the empirical formula for a compound that contains 0.0130 mol carbon, 0.0390 mol hydrogen, and 0.0065 mol oxygen.

C₂H₆O

Molecular Formula

100

How would you define molecular formula?

Unsimplified whole number ratio, gives exact number of atoms.

200

The empirical formula of a compound is C₂H₄. The molar mass of the molecule is 84 g/mol. What is the molecular formula?

C₆H₁₂

300

Find the molecular formula of a compound if n = 4 and the empirical formula is C₄Cl₅

C₁₆Cl₂₀

400

Carbon reacts with 15.53 g of an iron oxide compound to form carbon dioxide and 10.87 g solid iron. How much oxygen is in the compound?

4.66 grams of O₂