Chemical Quantities

vocabulary

100

What is the number of particles in one mole?

Avogadro's number, 6.022 x 10^23

200

The SI unit for measuring the amount of a substance.

The mole

300

The relative amounts of the elements in a compound can be expressed as this.

Percent Composition

400

the lowest whole number ratio of the atoms or moles of the elements in a compound.

empirical formula

500

A simple whole number multiple of the empirical formula.

molecular formula

mole conversions

100

3.5 mol C = ______g

42 g of C

200

1.6 x 10^24 molecules FeCl3 = _________ mol FeCl3

2.6 mol FeCl3

300

2.76 g Ar = ______ mol Ar

0.691 mol Ar

400

4.10 mol BaSO4 = _________ formula units

2.47 x 10^24 formula units BaSO4

500

6.58 g Mg = ____________ atoms Mg

1.63 x 10^23 atoms

concepts

100

What is the purpose of a mole?

To allow you to convert small amounts of substances into grams and particles.

200

Is this molecular or empirical? H2O2

Molecular

300

Is this molecular or empirical? NO2

empirical

400

How are empirical and molecular formulas similar?

They are both chemical formulas with letters that represent atoms and numbers that represent the amount of atoms.

500

How are molecular and empirical different?

Empirical is in simplest form. Molecular shows the exact amount of atoms. It is a multiple of the empirical formula.

percent composition

100

What is the percent composition for each element in CO?

C=43% O=57%

200

A compound is formed when 9.03 g Mg combines completely with 3.48g N. What is the percent composition of this compound?

Mg=72.2% N=27.8%

300

Calculate the percent by mass of nitrogen in NH4NO3.

35%

400

Calculate the grams of nitrogen in 125 g of NH4NO3.

43.8 g

500

Calculate the mass of hydrogen in 350 g ethane (C2H6)

70 g

chemical formulas

100

Calculate the empirical formula for 67.6% Hg, 10.8% S, 21.6% O

HgSO4

200

What is the empirical formula of a compound with the following percent composition? 62.1% C, 13.8% H, and 24.1% N.

C3H8N

300

Find the molecular formula of a compound whose molar mass is 62.0 g/mol and the empirical formula is CH3O

C2H6O2 or 2(CH3O)

400

A compound is 25.9% nitrogen and 74.1% oxygen. What is the empirical formula?

N2O5

500

Find the molecular formula of a compound that contains 56.36 g of oxygen and 43.64 g of phosphorus. The molar mass of the compound is 283.9 g/mol. 

P4O10