Mass–mass calculations Original Scenario-Based Practice

Questions

1. 1.

   Inside a twilight crystal cavern, an explorer powers a specialized carbide lamp to navigate subterranean chasms by hydrating calcium carbide according to the balanced equation $\text{CaC}_2(s) + 2\text{H}_2\text{O}(l) \rightarrow \text{Ca(OH)}_2(s) + \text{C}_2\text{H}_2(g)$. If the generator cartridge completely consumes exactly 192 g of $\text{CaC}_2$, what mass of acetylene gas ($\text{C}_2\text{H}_2$) is produced? (Molar masses: $\text{H} = 1\text{ g/mol}$, $\text{C} = 12\text{ g/mol}$, $\text{O} = 16\text{ g/mol}$, $\text{Ca} = 40\text{ g/mol}$)

   • A) 52 g
   • B) 108 g
   • C) 222 g
   • D) 78 g
2. 2.

   In an airborne citadel anchored above a storm-swept gas giant, an artificer purifies tungsten to craft lightning rods for energy harvesting. The high-temperature reduction process consumes solid tungsten(VI) oxide according to the balanced equation $\text{WO}_3(s) + 3\text{H}_2(g) \rightarrow \text{W}(s) + 3\text{H}_2\text{O}(g)$. If the reaction chamber completely converts exactly 116 g of $\text{WO}_3$, what mass of water vapor ($\text{H}_2\text{O}$) is generated? (Molar masses: $\text{H} = 1\text{ g/mol}$, $\text{O} = 16\text{ g/mol}$, $\text{W} = 184\text{ g/mol}$)

   • A) 27 g
   • B) 9 g
   • C) 54 g
   • D) 18 g
3. 3.

   To reinforce the heat shield of an atmospheric exploration skiff descending into the molten skies of a volcanic exoplanet, engineers synthesize elemental chromium using the carbothermic reduction of chromium(III) oxide according to the balanced equation $\text{Cr}_2\text{O}_3(s) + 3\text{C}(s) \rightarrow 2\text{Cr}(s) + 3\text{CO}(g)$. If the fabrication protocol requires the production of exactly 260 g of chromium, what minimum mass of $\text{Cr}_2\text{O}_3$ must be consumed? (Molar masses: $\text{C} = 12\text{ g/mol}$, $\text{O} = 16\text{ g/mol}$, $\text{Cr} = 52\text{ g/mol}$)

   • A) 190 g
   • B) 304 g
   • C) 760 g
   • D) 380 g
4. 4.

   To weld a fractured hull seam on an icy Jovian moon, an autonomous repair drone initiates a thermite reaction according to the balanced equation $\text{Fe}_2\text{O}_3(s) + 2\text{Al}(s) \rightarrow 2\text{Fe}(l) + \text{Al}_2\text{O}_3(s)$. If the structural repair requires the production of exactly 168 g of molten iron, what minimum mass of aluminum powder must be consumed in the reaction? (Molar masses: $\text{Al} = 27\text{ g/mol}$, $\text{Fe} = 56\text{ g/mol}$, $\text{O} = 16\text{ g/mol}$)

   • A) 81 g
   • B) 162 g
   • C) 40.5 g
   • D) 240 g
5. 5.

   A deep-sea research team stranded in a benthic trench habitat must scrub carbon dioxide from their life-support atmosphere using solid lithium hydroxide canisters. The environmental control unit relies on the reaction $2\text{LiOH}(s) + \text{CO}_2(g) \rightarrow \text{Li}_2\text{CO}_3(s) + \text{H}_2\text{O}(l)$ to capture the exhaled gas. If the crew's metabolic sensors indicate that exactly 132 g of $\text{CO}_2$ must be neutralized during an emergency shift, what minimum mass of $\text{LiOH}$ is required? (Molar masses: $\text{H} = 1\text{ g/mol}$, $\text{Li} = 7\text{ g/mol}$, $\text{C} = 12\text{ g/mol}$, $\text{O} = 16\text{ g/mol}$)

   • A) 144 g
   • B) 72 g
   • C) 36 g
   • D) 288 g

Answers and step-by-step solutions appear after you finish the test.