Stoichiometry Pre Test

Where does the mole ratio come from?

• the molar mass of the reactants in the balanced chemical equation

• the coefficients of the balanced chemical equation

• the subscripts of the products in the balanced chemical equation

• the group number of each element in the balanced chemical equation

Tags

NGSS.HS-PS1-7

NH₃ + 5 O₂ → 4 NO + 6 H₂O

What is the mole ratio of oxygen to water? (a)  

What is the mole ratio of NH₃ to NO? ​ (b)  

What is the mole ratio of NH₃ to oxygen? ​ (c)  

What is the mole ratio of H₂O to NH₃? ​ (d)  

• 6/5

• 4/4

• 4/5

• 6/4

• 4/6

• 5/6

• 5/4

• 6/6

FeS + 7 O₂ → 2 Fe₂O₃ + 4 SO₂

Place the numbers in the correct spots to solve this problem: how many moles of FeS will be needed to produce 13.72 moles of Fe₂O₃? (end amount is the answer)

g

h

i

e

6.86 mol FeS

2 mol Fe₂O₃

4 mol Fe₂O₃

7 mol O₂

27.44 mol FeS

4 mol FeS

4 mol SO₂

2 mol FeS

13.72 mol Fe₂O₃

13.72 mol FeS

Tags

NGSS.HS-PS1-7

Use the equation 2 Al + 3 Cl₂ ---> 2 AlCl₃.  If 30 g of aluminum and 80g of chlorine are reacted, identify the limiting reactant.

Tags

NGSS.HS-PS1-7

The blue numbers in the image below represent ________

• I don't know, and don't want to try

• coefficients

• subscripts

• none of the answers are correct

Calculate the molar mass of NH₄NO₂. Round to the nearest whole number.

Find the mass of 3.8 mol of H₂O. Round to the nearest tenth.

• 57.9 g

• 54.8 g

• 68.5 g

• 62.3 g

Tags

NGSS.HS-PS1-7

How many molecules of Octane would be found in 8.4 moles of Octane (C₈H₁₈)?

• 5.77 x 10²³

• 5.06 x 10²⁴

• 5.77 x 10²⁶

• 5.06 x 10²³

2Al + 3H₂SO₄ -> Al₂(SO₄)₃ + 3H₂
How many grams of Al₂(SO₄)₃ would be formed if 250g H₂SO₄ completely reacted with aluminum? Round your answer to the nearest whole number.

Tags

NGSS.HS-PS1-7

What is the limiting reactant if 10 moles of NH₃  react  with 30.0 moles of NO?
4NH₃+6NO --> 5N₂ + 6H₂O

• NH₃

• NO

• N₂

• water