Question

Difficulty: HardChemical Equations and Stoichiometric Calculations (Mass-Mass, Mass-Volume, Mole Relations)
Consider the catalytic oxidation of ammonia gas represented by the balanced chemical equation below:
4NH3(g)+5O2(g)4NO(g)+6H2O(g)4NH_3(g) + 5O_2(g) \rightarrow 4NO(g) + 6H_2O(g)
If 6.8 g6.8\text{ g} of ammonia gas reacts completely with excess oxygen gas at STP, calculate the volume of nitrogen(II) oxide gas and the volume of steam produced.
[H=1,N=14,O=16,Molar volume of gas at STP=22.4 dm3 mol1][H = 1, N = 14, O = 16, \text{Molar volume of gas at STP} = 22.4\text{ dm}^3\text{ mol}^{-1}]
Fill in the missing values in the statement below.
Answer:The volume of nitrogen(II) oxide gas (NONO) produced at STP is 【8.96】 dm³, and the volume of steam (H2OH_2O) produced at STP is 【13.44】 dm³.

Answer

The volume of nitrogen(II) oxide produced at STP is 8.96 dm³ and the volume of steam produced at STP is 13.44 dm³.
Molar mass of ammonia is 17 g/mol, meaning 6.8 g equals 0.4 mol of ammonia. According to the balanced equation, 4 moles of ammonia produce 4 moles of nitrogen(II) oxide gas and 6 moles of steam. Thus, 0.4 mol of ammonia yields 0.4 mol of nitrogen(II) oxide gas (0.4 * 22.4 = 8.96 dm³) and 0.6 mol of steam (0.6 * 22.4 = 13.44 dm³).

Step-by-Step Solution

1
Calculate the molar mass of ammonia (NH3NH_3)
Molar mass of NH3=14+(3×1)=17 g mol1NH_3 = 14 + (3 \times 1) = 17\text{ g mol}^{-1}
Required to convert the given mass of reactant into moles.
2
Calculate the number of moles of NH3NH_3 reacted
\text{Moles of } NH_3 = \frac{6.8\text{ g}}{17\text{ g mol}^{-1}} = 0.4\text{ mol}
Stoichiometric relations in chemical equations are expressed in mole ratios.
3
Determine the moles of NO(g)NO(g) and H2O(g)H_2O(g) produced using stoichiometric coefficients
From the balanced equation, 4 mol NH34 mol NO4\text{ mol } NH_3 \rightarrow 4\text{ mol } NO, so 0.4 mol NH30.4 mol NO0.4\text{ mol } NH_3 \rightarrow 0.4\text{ mol } NO.
Also, 4 mol NH36 mol H2O(g)4\text{ mol } NH_3 \rightarrow 6\text{ mol } H_2O(g), so Moles of H2O=64×0.4=0.6 mol\text{Moles of } H_2O = \frac{6}{4} \times 0.4 = 0.6\text{ mol}.
The coefficients in the balanced equation define the molar ratio between reactants and products.
4
Convert the moles of each gaseous product to volume at STP using molar gas volume
\text{Volume of } NO = 0.4\text{ mol} \times 22.4\text{ dm}^3\text{ mol}^{-1} = 8.96\text{ dm}^3 Volume of H2O=0.6 mol×22.4 dm3 mol1=13.44 dm3 \text{Volume of } H_2O = 0.6\text{ mol} \times 22.4\text{ dm}^3\text{ mol}^{-1} = 13.44\text{ dm}^3
At STP, 1 mole1\text{ mole} of any ideal gas occupies 22.4 dm322.4\text{ dm}^3.

Key Concept

Mass-Volume Stoichiometry at STP
Estimated Time:2m 0s
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