Respuesta :

Space

Answer:

514 kJ

General Formulas and Concepts:

Atomic Structure

  • Reading a Periodic Table
  • Elements
  • Compounds
  • Moles

Stoichiometry

  • Analyzing Reactions rxn
  • Using Dimensional Analysis

Explanation:

Step 1: Define

Identify

[Given] rxn (balanced): 2Si (s) + 2Cl₂ → 2SiCl₂ (g) + 687 kJ

[Given] 106 g Cl₂

[Solve] kJ heat

Step 2: Identify Conversions

[rxn] 2 mol Cl₂ → 687 kJ

[PT] Molar Mass of Cl: 35.45 g/mol

Molar Mass of Cl₂: 2(35.45) = 70.9 g/mol

Step 3: Stoichiometry

  1. [DA] Set up:                                                                                                       [tex]\displaystyle 106 \ g \ Cl_2(\frac{1 \ mol \ Cl_2}{70.9 \ g \ Cl_2})(\frac{687 \ kJ}{2 \ mol \ Cl_2})[/tex]
  2. [DA] Divide/Multiply [Cancel out units]:                                                           [tex]\displaystyle 513.554 \ kJ[/tex]

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

513.554 kJ ≈ 514 kJ

Topic: AP Chemistry

Unit: Thermochemistry

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