Unit 5 Review - CHEM

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

A scientist calculated he should produce 12.3 grams of product in his experiment. He collects 10.1 grams. What is his percent yield?

• 82%
• 10.1 %
• 0.82%
• 100%

Which has a greater mass: 1 mole of scandium or 2 moles of boron?

• scandium
• boron
• neither
• more information is needed.

How many moles of carbon atoms are there in 5g of carbon?

• 60 mol
• 17 mol
• 0.42 mol
• 7 mol

How many moles of (NH₄)₂O are present in 74.9 g?

• 3,907.0  moles
• 1.44 moles
• 8.67x10²³moles
• 0.79 moles

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

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

Tags

NGSS.HS-PS1-7

The limiting reactant

• slows the reaction down
• is used up first
• is the reactant that is left over
• controls the speed of the reaction

What is the limiting reactant if 10.0 moles of NH₃  react  with 30.0 moles of NO?
4NH₃ + 6NO → 5N₂ + 6H₂O

• NH₃
• NO
• N₂
• H₂O

Tags

NGSS.HS-PS1-7

How many moles are there in 12.7g of CaF₂?

• 0.20 mol
• 1,000.76 mol
• 6.14 mol
• 0.16 mol

What is the mass of 9.4 moles of B₂(Cr₂O₇)₃?

• 6.41 x 10²²g
• 5.67x10²⁴ g
• 49.11 g
• 4,339.23 g