# Problem: Meals-ready-to-eat (MREs) are military meals that can be heated on a flameless heater. The heat is produced by the following reaction: Mg(s) + 2 H2O(l) → Mg(OH)2(s) + H2(g).Calculate the number of grams of Mg needed for this reaction to release enough energy to increase the temperature of 76 mL of water from 26˚C to 76˚C.

###### FREE Expert Solution

ΔH˚rxn = –6.827 × 105 J/mol

$\overline{)\mathbf{q}\mathbf{=}\mathbf{mc}\mathbf{∆}\mathbf{T}}\phantom{\rule{0ex}{0ex}}\mathbf{q}\mathbf{=}\mathbf{mc}\left({T}_{f}-{T}_{i}\right)$

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###### Problem Details

Meals-ready-to-eat (MREs) are military meals that can be heated on a flameless heater. The heat is produced by the following reaction: Mg(s) + 2 H2O(l) → Mg(OH)2(s) + H2(g).

Calculate the number of grams of Mg needed for this reaction to release enough energy to increase the temperature of 76 mL of water from 26˚C to 76˚C.