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Chemistry - Stoichiometry Test Review


2. Solid Sodium and chlorine gas react to produce solid sodium chloride:

2Na + Cl2  = 2NaCl


a. How many moles of chlorine gas (Cl2) would react with 5.0 moles of sodium (Na)?
Solution: 

2(a)

NaCl2

Per Equation or Theoretically

2 moles1 mole
Actual5 molesx mole?




2/5 = 1/x; 2x = 5; x = 2.5 moles, Answer.


b. Determine the mass of NaCl that can be produced from 24.7 g Na.

Solution: 

2(b)NaNaCl
Per Equation or Theoretically2 x 22.99  = 45.98 g2 x (22.99 + 35.45)g = 116.88 g
Actual24.7 gx?





45.98/24.7 = 116.88/x; x = 62.8 g, Answer


c. How many molecules of Cl2 would be needed to react with 24.7 g Na?

​Solution: 

2(c)NaCl2
Per Equation or theoretically45.98 g6.02 x 10^23 molecules
Actual24.7 gx?




45.98/24.7 = 6.02 x 10^23 / xx = 3.24 x 10^23 molecules, Answer


3.

2C8H18 + 25O2 = 16CO2 + 18H2O


a. If 27.3 g of C8H18 are burned, what mass of water will be produced?
Solution: 


C8H18H2O
Per Equation or theoretically

2x(8x12 +18x1)

= 228 g

18x(2+16)

=324 g

Actual
27.3 gx?





228/27.3 = 324/x; x = 324x27.3/228 = 38.7 g of H2O, Answer


b. How many molecules of CO2 will be produced, using the same given quantity from part a?

Solution: 


C8H18
CO2
Per Equation or theoretically
228 g 16 x 6.02 x 10^23 molecules
Actual
27.3 gx?





228/27.3 = 16x6.02x10^23/xx = 1.15 x 10^24 molecules of CO2, Answer


c. What volume of CO2 gas is produced, using the same quantity from part a (at STP)?

Solution: 


C8H18CO2
Per Equation or theoretically
228 g16 x 22.4 L
Actual
27.3 gx?




228/27.3 = 16x22.4/x; x = 42.9 L of CO2, Answer