WORKSHEET stoic

Question

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____ CH4+___O2---->____CO2+____H2O

1)How many moles of oxygen gas are needed to produce 2.14 moles of water?

Anewer ____ mol

2) How many moles of oxygen can be formed from 67 grams of carbon dioxide?

Answer____ mol

3) How many grams carbon dioxide can be formed from 29 grams of methane (carbon tetrahidride)

Anewer____ grams

Answer 1

The balanced chemical equation is: 1CH₄ + 2O₂ → 1CO₂ + 2H₂O

The coefficients in the balanced chemical equation is the molar ratio fo each specie. We can use this ratio of each specie to interconvert between each of them.

1. 2.14 mol H₂O * (2 mol O₂ / 2 mol H₂O) = 2.14 mol O₂
2. We multiply by this 2/2 ratio because those are molar ratios of each specie. Notice the units along the diagonal cancel out.
3. 67 g CO₂ * (1 mol CO₂ / 44.01 g CO₂) * (2 mol O₂ / 1 mol CO₂) = 3.04 mol O₂
4. The first step is converting the grams of CO₂ into moles of CO₂ by dividing by its molar mass. Then, since we are in moles, we can interconvert between species by using the molar ratio from the balanced chemical equation.
5. 29 g CH₄ * (1 mol CH₄ / 16 g CH₄) * (1 mol CO₂ / 1 mol CH₄) * (44.01 g CO₂ / 1 mol CO₂) = 79.77 g CO₂
6. The first step is convert grams of CH₄ into moles of CH₄. Then, we convert from moles of CH₄ into moles of CO₂ by using the molar ratio from the balanced chemical equation. Finally, we convert the moles of CO₂ into grams of CO₂ by multiplying by the molar mass.