Moles!

One step conversions

100

The number of particles in one mole.

6.02 x 10²³ particles

200

The mass of 2 moles of beryllium (Be)

18.02 g

300

The number of moles in 101.02 g of Sulfur

3.15 moles

400

The number of moles in 2.35 x 10²⁴ atoms of sodium

3.9 moles

500

The mass of 7.80 moles of H₂O₂

265 g

Two step conversions

100

To change from the mass of a substance to the number of particles you should do these two general steps.

1 divide by the molar mass

2. multiply by 6.02 x 10²³

200

The number of atoms in 24.02 g of Carbon.

1.2 x 10²⁴ atoms

300

The mass of 

2.2 x 10²⁴ atoms of iron (Fe).

204 g

400

How many molecules are there in 75.0g of sugar (C12H22O11)?

1.32x10²³ molecules

500

What is the volume occupied by 10.0g of H2S at STP?

6.58L

Multi-step conversions

100

What is the mass of 2x10⁶ CO molecules?

9x10^-17 g

200

How many oxygen molecules are in 25 g of CO₂?

3.4x10²³

300

What is the volume of 16.5g of AsH3 at STP?

4.74L

400

What is the density (in g/L) of CO₂ at STP?

1.96g/L

500

What is the molar volume of gold, having a density of 19.31g/mL?

98.04mol/L

EmpiricalFormulas

100

True or false: The empirical formula shows the lowest ratio of the elements in a compound.

True

200

What is the empirical formula of the following:

C₃H₆O₃

C₆H₁₂O₆

C₅H₁₀O₅

CH₂O

300

When calculating the empirical formula, a student determines that the substance has: 

2.02 moles Chlorine, 

2.02 moles Carbon, and 

4.04 moles hydrogen.  

ClCH₂

400

This is the empirical formula of a substance that is composed of 1.11g Se and 1.61g F.

SeF₆

500

The empirical formula for a substance that is made of 48.6% carbon, 8.16% hydrogen, and 43.2 % oxygen.

C₃H₆O₂

Molecular Formulas

100

True or false: A molecular formula shows the ratio of elements that actually exist.

True

200

This would be the molecular formula for a compound with a molar mass of 88.12g/mol and an empirical formula of C₂H₄O

C₄H₈O₂

300

A gas has an empirical formula of CH₂. Its molar mass is 4 times greater than the molar mass of C₂H₄. What is the molecular formula of the gas?

C₈H₁₆

400

This would be the molecular formula for a compound that has an empirical formula of CH, and 450mL of the gas at STP has a mass of 0.522g

C2H2

500

A compound contains only nitrogen and oxygen is 30.4% nitrogen by mass and 69.6% oxygen by mass. This is the molecular formula of the compound if the molecular molar mass is 92 g/mol. 

N₂O₄