Multiple Choice
When 10.0 g of AgNO3 is added to an aqueous solution containing excess NaCl, what mass of AgCl will precipitate? (Assume complete reaction and that AgNO3 is the limiting reagent.)
26
views
3. Chemical Reactions
Stoichiometry
Struggling with General Chemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Given that air is approximately 21% oxygen by mole, how many moles of propane (C_3H_8) are needed to completely react with the oxygen present in 24.0 moles of air?
A
5.04 moles
B
0.70 moles
C
2.86 moles
D
1.71 moles
Verified step by step guidance1
Write the balanced chemical equation for the combustion of propane (C\_3H\_8):
\[ C\_3H\_8 + 5O\_2 \rightarrow 3CO\_2 + 4H\_2O \]
Determine the moles of oxygen (O\_2) present in 24.0 moles of air, knowing that air is approximately 21% oxygen by mole:
\[ \text{moles of } O\_2 = 0.21 \times 24.0 \]
Use the stoichiometric ratio from the balanced equation to relate moles of oxygen to moles of propane. According to the equation, 1 mole of propane reacts with 5 moles of oxygen:
\[ \text{moles of } C\_3H\_8 = \frac{\text{moles of } O\_2}{5} \]
Substitute the moles of oxygen calculated in step 2 into the equation from step 3 to find the moles of propane needed to react completely with the oxygen in 24.0 moles of air.
Interpret the result as the amount of propane required for complete combustion with the oxygen available in the given amount of air.
Related Videos
Related Practice
