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

Assuming that the specific heat capacity for both, we can rewrite the equation:

q = m * Cp * (T2 - T1) to q = m * (T2 - T1)

Equating them to each other we have:

m1 * (T2 - T1) = m2 * (T2 - T3)
0.261 * (T2 - 25) = 0.127 * (T2 - 95)
T2 = -41.34 degrees Celsius