Moles
Stoichiometry
Mole ratios
limiting reactant
100

A weather balloon contains 25 moles of Helium (He) gas.How many grams of Helium are in the water ballon

100 grams

100

Consider the reaction where Hydrogen gas reacts with Oxygen to form water: 2H2+O2→2H2O. If you start with 4 moles of H2, how many moles of O2 are needed for a complete reaction?

2 moles 

100

2H2 + O2 --> 2H20

If you have 10 moles of Hydrogen (H2), how many moles of Oxygen (O2) do you need to react with it completely?

ratio: 2 moles of H: 1 mole of O2

Answer: 5 Moles


100

Equation: 2H2 + O2 ---> 2H2O

You have 10 moles of H2 and 7 moles of O2

Which is the limiting reactant, and how many moles of H2O can you make?

H2 is limiting; you can make 10 moles of H2O.

200

You have a tube of Magnesium with a mass of 48.62 grams. How many moles of Magnesium are present?

2 moles

200

In the reaction N2 + 3H2 --> 2NH3, if you produce 10 moles of Ammonia (NH3), how many moles of Nitrogen (N2) were used?

5 moles

200

If you produce 6 moles of Water (H2O), how many moles of Hydrogen (H2) did you start with?

ratio: 2 moles of H2 : 2 moles of H2O

answer:6 moles of H2

200

Equation: C + O2 ---> CO

You have 3 moles of Carbon and 5 moles of Oxygen gas.

Which is the limiting reactant, and how many moles of CO2 are produced?


Carbon is limiting; you produce 3 moles of CO2.

300

A specialized neon sign contains 0.5 moles of Neon gas. What is the mass of the gas in grams?

10.09 grams

300

You react 54.0 grams of Aluminum (Al) with excess Oxygen to form Aluminum Oxide (4Al + 3O2 -->2Al2O3). How many moles of Aluminum are you starting with? (Atomic mass of Al = 27.0 g/mol)

2 moles

Half court shot?(5 points)

300

N2 + 3H2 --> 2NH3

You want to produce 8 moles of Ammonia (NH3). How many moles of Hydrogen gas (H2) are required?

ratio: 3 moles of H2 : 2 moles of NH3

Answer: 12 moles of H2

300

N2 + 3H----> 2NH3

You have 2 moles of N2 and 9 moles of H2.

What is the mass of Ammonia (NH3) produced?

N2 is limiting: You make 68 grams

Take 2 shots!

400

A high-tech laboratory has a sample of Gold (Au) containing 1.8066x1024 atoms. How many moles of Gold are in the sample?

3 moles

Double points!

400

Using the reaction C+O2→CO2, if you burn 60.0 grams of Carbon (C), how many moles of Oxygen gas (O2) are consumed? (Atomic mass of C = 12.0 g/mol)

5 moles

Three pointer!

400

2Na + 2HCl ---> 2NaCl + H2

You drop a piece of Sodium (Na) into the acid, and it produces exactly 3 moles of Hydrogen gas (H2). How many grams of Sodium did you start with?

ratio: 2:1

Answer: 138 grams

Double Points!

400

2Mg + Cl-----> MgCl2You have 48.6 grams of Mg and 5 moles of Cl2

How many moles of MgCl2 are formed?

Mg is limiting; you form 2 moles of MgCl2

Double points!!!

500

A pure copper pipe has a mass of 127.10 grams. Calculate the total number of atoms in the pipe. This is a two-step equation

1.2044x1024 

three pointer!

500

Iron reacts with Oxygen to form rust 4Fe + 3O2 ---> 2Fe2O3. If you have 1.2044x1024 atoms of Iron (Fe), what mass of Iron do you have?

 (Atomic mass of Fe = 55.85 g/mol, Avogadro's Number = 6.022x1023)

111.70 grams

Triple points!!

500

4Al + 3O2 ---> 2Al2O3

You have 162 grams of Aluminum (Al). How many moles of Oxygen (O2) are required to react with all of it?

Answer: 6 moles of Al

Ratio 4: moles of Al to 3 moles of O2.

Answer:4.5 moles of O

Triple points

500

2Al + 3S ----> Al2S3

You have 108 grams of Aluminum and 6 moles of Sulfur

Which is limiting, and how many grams of the excess reactant are left over?

They are in a perfect ratio! Neither is limiting; both are consumed completely.

 You produce 2 moles of Al2S3

Half Court?? (5 points)