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Ch.3 - Chemical Reactions and Reaction Stoichiometry
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Brown 14th EditionCh.3 - Chemical Reactions and Reaction Stoichiometry문제 71
3장, 문제 71

The complete combustion of octane, C8H18, produces 5470 kJ of heat. Calculate how many grams of octane are required to produce 20,000 kJ of heat.

검증된 단계별 안내
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Step 1: Write the balanced chemical equation for the complete combustion of octane: \[ 2 \text{C}_8\text{H}_{18} + 25 \text{O}_2 \rightarrow 16 \text{CO}_2 + 18 \text{H}_2\text{O} \].
Step 2: Note that the combustion of 2 moles of octane produces 5470 kJ of heat. Therefore, calculate the heat produced per mole of octane by dividing 5470 kJ by 2.
Step 3: Determine the number of moles of octane needed to produce 20,000 kJ of heat by dividing 20,000 kJ by the heat produced per mole of octane calculated in Step 2.
Step 4: Calculate the molar mass of octane (C8H18) by adding the atomic masses of carbon (C) and hydrogen (H): \[ 8 \times 12.01 \text{ g/mol} + 18 \times 1.01 \text{ g/mol} \].
Step 5: Convert the moles of octane needed (from Step 3) to grams by multiplying the number of moles by the molar mass of octane calculated in Step 4.

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows us to calculate how much of a substance is needed or produced based on the balanced chemical equation. In this case, understanding the stoichiometric coefficients will help determine the amount of octane required to produce a specific amount of heat.
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가이드 코스
01:16
Stoichiometry Concept

Heat of Combustion

The heat of combustion is the amount of energy released when a substance undergoes complete combustion with oxygen. For octane, the heat of combustion is given as 5470 kJ per mole. This value is crucial for calculating how many grams of octane are needed to achieve a desired energy output, such as 20,000 kJ in this problem.
추천 영상:
가이드 코스
02:24
Combustion Apparatus

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). For octane (C8H18), the molar mass can be calculated by summing the atomic masses of its constituent elements. This concept is essential for converting between moles of octane and grams, allowing us to find the mass needed to produce the specified amount of heat.
추천 영상:
가이드 코스
02:11
Molar Mass Concept
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교과서 질문

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교과서 질문

(a) Define the terms limiting reactant and excess reactant.

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교과서 질문

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교과서 질문

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(b) Why are the amounts of products formed in a reaction determined only by the amount of the limiting reactant?

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