#### Transcript N 2 (g)

```Challenge Problem
• When nitrogen and hydrogen react, they
form ammonia gas, which has the
formula NH3. If 56.0 g of nitrogen are
used up in the reaction, how many grams
of ammonia will be produced?
N2 (g) + 3H2 (g)  2NH3 (g)
? g NH3 = 56.0 g N2
1 mol N2 2 mol NH3 17g NH3
=
28g N2
1 mol N2
1 mol NH3
68g NH3
Episode 802
• Sodium metal reacts with oxygen to produce solid
sodium oxide. How many grams of sodium must react
to produce 42.0 grams of sodium oxide?
4Na (s) + O2 (g)  2Na2O (s)
? g Na = 42.0g Na2O 1 mol Na2O
62g Na2O
4 mol Na
23g Na
2 mol Na2O
1 mol Na
= 31g Na
• When 12.0 grams of hydrogen reacts with oxygen,
how many grams of water are produced?
2H2 (g) + O2 (g)  2H2O (l)
? g H2O = 12.0g H2 1 mol H2 2 mol H2O 18g H2O
2g H2
2 mol H2 1 mol H2O
= 108g H2O
Episode 802
• Actual Yield
– Amount of product produced when the
reaction is performed in a lab
• Theoretical Yield
– Amount of product expected to be
produced based on the balanced equation
and the amount of reactants
– Calculated using stoichiometry
• Percent Yield
– (actual yield/theoretical yield) x 100%
Episode 802
Percent Yield in Lab
• Actual yield of CO2 = 0.13g
– (from lab data)
• Calculated theoretical yield from the
balanced equation:
NaHCO3 + HCl  NaCl + CO2 + H2O
? g CO2 = 0.23g NaCO3
1mol NaCO3 1mol CO2
44g CO2
84g NaCO3 1mol NaCO3 1mol CO2
= 0.12g CO2
% yield =
0.13g
0.12g
x 100 =
108%
Episode 802
• What is the % yield of carbon dioxide
when 5.99 grams of propane are burned
and 12.052 grams of carbon dioxide are
collected?
C3H8 + 5O2  3CO2 + 4H2O
? g CO2 = 5.99g C3H8 1 mol C3H8 3 mol CO2 44g CO2
44g C3H8 1 mol C3H8 1 mol CO2
= 17.97g CO2
% yield =
12.052g
17.97g
x 100 =
67%
Episode 802
```