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

• 6

• 2

• 3

• 1

Tags

NGSS.HS-PS1-7

Cl₂ + 2KBr → Br₂ + 2KCl
How many grams of potassium chloride (KCl) can be produced from 356 g of potassium bromide (KBr)? (show work)

KBr molar mass = 119.002 g/mol

KCl molar mass = 74.551 g/mol

Tags

NGSS.HS-PS1-7

B₂H₆ + O₂ -->  HBO₂ + H₂O
 What mass of O₂ will be needed to burn 36.1 g of B₂H₆? (show work)

B₂H₆ molar mass = 27.67 g/mol

O₂ molar mass = 32.00 g/mol

• 13.8 g O₂

• 3.86 mol of O₂

• 125.2 g O₂

• 108.3 g O₂

Balance the following reaction :
 
CaC₂(s)   +   H₂O(l)   -->   C₂H₂(g)   +   Ca(OH)₂(aq)

• 1,2,2,2

• 1,2,1,1

• 2,1,1,1

• 2,1,2,1

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

• Write a Balanced Equation

• Panic

• Write an Unbalanced Equation

• Avogadro's Number

CH₄ + 2H₂O --> CO₂ + 4H₂
What is the limiting reactant when 20g CH₄ react with 15g H₂O? (show work)

CH₄ molar mass = 16.042 g/mol

H₂O molar mass = 18.02 g/mol

Tags

NGSS.HS-PS1-7

Theoretical yield = 73g
Actual yield = 62g
Calculate the percent yield. (show work)

• 1.16%

• 116%

• 85%

• 76%

50g of Silver nitrate reacts with 8g of copper in a single displacement reaction. If this was done in the lab and we recovered 24.82g of silver from the reaction, what is the percent yield? (show work)
Silver nitrate molar mass = 169.87 g/mol

Copper nitrate molar mass = 187.57 g/mol

Tags

NGSS.HS-PS1-7

The ____ in a balanced chemical reactions gives the MOLE RATIO used in stoichiometry problems.

• coefficients

• reactants

• subscripts

• products

In a lab where students reacted copper with silver nitrate. Silver, a product, was dried and massed at 8.3g. The accepted value is 9.0g, what is the percent error for this experiment? (show work)

Tags

NGSS.HS-PS1-7