Ch. 4 Jeopardy!

Finding Molar Mass

100

What is the molar mass of silicon?

28.086 g/mol

200

What is the molar mass of SrS?

119.6 g/mol

300

What is the molar mass of cesium chloride?

(CsCl) 

168.35 g/mol

400

What is the molar mass of potassium carbonate?

K₂CO₃

138.2 g/mol

Using molar mass

100

How can you convert grams of carbon into moles of carbon?

divide by molar mass

200

Convert 101 g of iron into moles of iron.

1.81 mol of iron

300

A chemist determined by measurements that 0.0550 moles of potassium participated in a chemical reaction. Calculate the mass of potassium that participated in the chemical reaction.

2.15 g of potassium

400

A chemist measured the amount of cesium chloride produced during an experiment. She finds that 19.6 g of cesium chloride is produced. Calculate the number of moles of cesium chloride produced.

0.116 mol of CsCl

Molar Ratios and Avogadro's Number

100

What is Avogadro's number? How can you use this in a conversion?

Avogadro's number = 6.022 x 10²³

1 mole = 6.022 x 10²³ atoms/molecules/ions

200

The chemical formula for tetraborane is B₄H_10. What is the molar ratio of hydrogen to tetraborane?

10 mol_H / 1 mol_tetraborane

300

You have 3 moles of hydrazine (N₂H₄). How many molecules of hydrazine do you have?

1.806 x 10²⁴ molecules

400

Calculate the mass of iron(III) oxide (Fe₂O₃) that contains a billion (1.000 x 10⁹) oxygen atoms.

8.839 x 10^-14 g

All 3

100

You have 12 g of hydrazine (N₂H₄). How could you convert from grams of hydrazine to atoms of nitrogen?

(Don't actually do any math)

grams_N2H4 → mol_N → atoms_N

use molar mass, then multiply by Avogadro's number

200

Calculate the number of hydrogen atoms in a 50 g sample of camphor (C₁₀H₁₆O).

3.16 x 10²⁴ atoms

300

Calculate the mass of forsterite (Mg₂SiO₄) that contains a million (1.00 x 10⁶) magnesium atoms.

1.17 x 10^-6 g

400

Calculate the number of carbon atoms in 21 g of magnesium cyanide. (Hint: be careful with the molecular formula)

Mg(CN)₂

3.31 x 10²³ atoms