Transition metals, alloys and corrosion: แบบฝึกหัด

Calculate the volume of nitrogen gas, in \( \text{dm}^{3} \), required to react with \( 18.0\text{ dm}^{3} \) of hydrogen gas to produce ammonia, assuming all gas volumes are measured at the same temperature and pressure.
\( N_{2}(g) + 3H_{2}(g) \rightarrow 2NH_{3}(g) \)

Consider the production of ethanol by the fermentation of glucose:
\(C_{6}H_{12}O_{6} \rightarrow 2C_{2}H_{5}OH + 2CO_{2}\)

Calculate the atom economy for the production of ethanol in this reaction.
(Relative atomic masses: \(C = 12, H = 1, O = 16\))

The chemical \( N_{2}O_{4} \) is in dynamic equilibrium with \( NO_{2} \) as shown in the equation below:
\( N_{2}O_{4}(g) \rightleftharpoons 2NO_{2}(g) \)
The forward reaction is endothermic (\( \Delta H = +58\text{ kJ mol}^{-1} \)). Which of the following changes would shift the position of equilibrium to the right?

Calculate the volume of oxygen gas (at room temperature and pressure) required to react completely with 4.6 g of sodium to form sodium oxide.
\( 4Na(s) + O_{2}(g) \rightarrow 2Na_{2}O(s) \)
(Relative atomic mass: \( Na=23 \); Molar volume of gas = \( 24\text{ dm}^{3}\text{ mol}^{-1} \))

A student reacts 8.00 g of methane (\(CH_{4}\)) with an excess of oxygen. After the reaction, 15.4 g of carbon dioxide (\(CO_{2}\)) is collected.
The equation for the reaction is:
\(CH_{4} + 2O_{2} \rightarrow CO_{2} + 2H_{2}O\)
Calculate the percentage yield of carbon dioxide.
(Relative atomic masses: \(C = 12, H = 1, O = 16\))

Calculate the volume of oxygen gas required, at room temperature and pressure (RTP), to react completely with 6.0 g of ethane (\(C_2H_6\)) in a combustion reaction.
\(2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O\)
(Relative atomic masses: \(C = 12, H = 1\); Molar volume of gas at RTP = \(24 \text{ dm}^3 \text{ mol}^{-1}\))

A chemical manufacturer needs to produce a specific ester.
Explain why they might choose a reaction pathway with a lower percentage yield if that pathway has a significantly higher atom economy and produces no toxic by-products.