StoichiometryStoichiometry

ProblemProblem

What mass of water is produced when What mass of water is produced when 15.8 g of NH15.8 g of NH3 3 reacts with 21.8 g of Oreacts with 21.8 g of O2 2

to produce NO gas and water?to produce NO gas and water?

What is the first step?What is the first step?

• Balance the Equation

• Divide NH3 by O2 to find the difference between the two

• Add the reactants to find the total grams produced

Correct!!!Correct!!!

Good WorkGood Work AwesomeAwesome FantasticFantastic

Sorry…WRONGSorry…WRONG

This is NOT a step in STOICHIOMETRYThis is NOT a step in STOICHIOMETRY—Remember to balance the equation —Remember to balance the equation before doing any other stepbefore doing any other step

Sorry…WRONGSorry…WRONG

This step is incorrect and is not a part of This step is incorrect and is not a part of STOICHIOMETRY—balance the STOICHIOMETRY—balance the equation FIRSTequation FIRST

How do you balance this How do you balance this Equation?Equation?

NHNH3 3 + O+ O2 2 NO +NO + HH22OO

Balancing The Equation…Balancing The Equation…

22NHNH3 3 + O+ O2 2 22NO + NO + 33HH22OO

Is this how you set up Is this how you set up the problem?the problem?

OmolH

OgHx

molNH

OmolHx

gNH

molNHxgNH

2

2

3

2

3

33

1

02.18

2

3

04.17

18.15

OmolH

OgHx

molO

OmolHx

gO

molOxgO

2

2

2

2

2

22

1

02.18

1

3

32

18.21

True False

Correct!!!Correct!!!

WRONG! How else would WRONG! How else would you set it up? Shown is you set it up? Shown is the correct waythe correct way

Finally, Solving the Finally, Solving the Equation!!!Equation!!!

OmolH

OgHx

molNH

OmolHx

gNH

molNHxgNH

2

2

3

2

3

33

1

02.18

2

3

04.17

18.15 = (15.8x1x3x18.02)/(17.04x2x1)

=(21.8x1x3x18.02)/(32x1x1)OmolH

OgHx

molO

OmolHx

gO

molOxgO

2

2

2

2

2

22

1

02.18

1

3

32

18.21

=25.06 g H2O

=32.83 G H2O