Molar Ratios 8th

What is the first thing you must do to solve a stoichiometry problem?

• Write a Balanced Equation
• Panic
• Write an Unbalanced Equation
• Ask for help

For the Balanced Reaction:
3 Mg + 1 Fe₂O₃ → 3 MgO + 2 Fe;
What is the Ratio of moles of Mg to moles Fe?

• 3mol Mg / 2 mol Fe
• 2 mol Mg/ 3 mol Fe
• 1 mol Fe/ 2 mol Fe
• 3 mol MgO / 2 mol Fe

Tags

NGSS.HS-PS1-7

You need 2 pieces of bread, 1 tablespoon of peanut butter and 2 tablespoons of jelly to make a sandwich. 
If you have 10 pieces of bread, 4 tablespoons of peanut butter and 20 tablespoons of jelly, what is the limiting reactant?

• bread
• jelly
• peanut butter
• sandwich

You need 2 pieces of bread, 1 tablespoon of peanut butter and 2 tablespoons of jelly to make 1 sandwich. 
If you have 10 pieces of bread, 5 tablespoons of peanut butter and 10 tablespoons of jelly, how many sandwiches can you make?

• 10 sandwiches
• 3 sandwiches
• 15 sandwiches
•  5 sandwiches

What is a Limiting Reagent?

• speeds up a reaction
• what you run out of first
• what you have left over
• slows down a reaction

Tags

NGSS.HS-PS1-7

What is a Excess Reagent?

• amount you end with
• what you run out of first
• what you have left over
• what you start with

2H₂   +   O₂  →  2H₂O
How many moles of water can be produced if 8 moles H₂ are used?

• 4 moles
• 8 moles
• 16 moles
• 2 moles

Tags

NGSS.HS-PS1-7

Mole ratios are obtained from the

• balanced chemical equation
• periodic table
• molar mass
• our minds

Tags

NGSS.HS-PS1-7

N₂ +  3H₂ → 2NH₃ 
How many moles of hydrogen are needed to react with 5 moles of nitrogen?

• 6 mol
• 2 mol
• 3 mol
• 15 mol

Tags

NGSS.HS-PS1-7

Using the following equation:
Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(l)
How many moles of iron can be made from  6 moles H₂? 

• 4 moles Fe
• 6 moles Fe
• 9 moles Fe
• 2 moles Fe

Tags

NGSS.HS-PS1-7