Anonymous
Anonymous asked in Science & MathematicsChemistry · 2 months ago

According to the following thermochemical equation, what mass of HF (ing) must react in order to produce 345 kJ of energy?Assume excess SiO2?

According to the following thermochemical equation, what mass of HF (in g) must react in order to produce 345 kJ of energy? Assume excess SiO2.

SiO2(s) + 4 HF(g) → SiF4(g) + 2 H2O(l) ΔH°rxn = -184 kJ

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  • 2 months ago

    According to the thermochemical equation, reaction of 4 mol HF produces 184 kJ of energy.

    When 345 kJ of energy is produced, moles of HF reacted = (4 mol) × (345/184) = 7.5 mol

    Molar mass of HF = (1.0 + 19.0) g/mol = 20.0 g/mol

    Mass of HF reacted = (7.5 mol) × (20.0 g/mol) = 150 g

    ====

    OR:

    (4 mol HF / 184 kJ) × (345 kJ) × (20.0 g HF / 1 mol HF)

    = 150 g HF

  • david
    Lv 7
    2 months ago

    1. find molar mass (MM) of HF

    2. MM/1mole X 4mole/184KJ X 345KJ >>>> use a calculator .. this gives the answer

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