Question

According to the following thermochemical equation, what mass of H2O (in g) must form in order to produce 3900 kJ of energy?
SiO2(s) + 4 HF(g) → SiF4(g) + 2 H2O(l) ΔH°rxn = -184 kJ SiO2(s) + 4 HF(g) → SiF4(g) + 2 H2O(l) ΔH°rxn = -184 kJ 216 g 382 g 763 g 408 g 272 g

Answer 1

Answer:

763 g

Explanation:

Let's consider the following thermochemical equation.

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

From the enthalpy of the reaction (ΔH°rxn), we can affirm that 184 kJ are released when 2 moles of H₂O(l) are produced. Taking into account that the molar mass of H₂O is 18.01 g/mol, the mass of water formed to produce 3900 kJ of energy is:

$-3900kJ.\frac{2molH_{2}O}{-184kJ} .\frac{18.01gH_{2}O}{1molH_{2}O} =763gH_{2}O$