Question

# Mg reacts with H+ (aq) according to Mg(s)+2H+(aq)\to Mg_2+(aq)+H_2(g) Suppose that 0.524 g of Mg is reacted with 60.o ml of 1.0 M H+(aq). Assume that

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Mg reacts with H+ (aq) according to
$$\displaystyle{M}{g{{\left({s}\right)}}}+{2}{H}+{\left({a}{q}\right)}\to{M}{g}_{{2}}+{\left({a}{q}\right)}+{H}_{{2}}{\left({g}\right)}$$
Suppose that 0.524 g of Mg is reacted with 60.o ml of 1.0 M H+(aq). Assume that the density of the H+ (aq) solution os 1.00 g/ml,and that its specific heat capacity equals that of water. Theinitial and final temperatures are 22.0 degree celsius and 65.8degree celsius.
a) Is the reaction endothermic or exothermic?
b) Calculate $$\displaystyle\triangle{H}$$ of of th reaction. Use correct sigs andgive units.
c) Calculate the $$\displaystyle\triangle{H}$$ of the reaction per mole of magnesium.

2021-02-16
$$\displaystyle{M}{g{{\left({s}\right)}}}+{2}{H}^{+}{\left({a}{q}\right)}\to{M}{{g}^{{{2}+}}{\left({a}{q}\right)}}+{H}_{{2}}{\left({g}\right)}$$
Part a)
Reaction of Metallic magnesium with acid is an exothermic reaction
Part b)
We have, Moles of $$\displaystyle{M}{g}={\frac{{\text{Mass}}}{{\text{Molar mass}}}}={\frac{{{0.524}}}{{{24.305}}}}={0.02156}\ {m}{o}{l}$$
Now, mass of the solution = Mass of water + Mass of Mg = 0.524 + 60.0 = 60.524 g
$$\displaystyle{q}=-{m}{c}\triangle{T}$$
Where q is the heat released
c is the specific heat
$$\displaystyle\triangle{T}$$ is the temperature change
Therefore, $$\displaystyle{q}={60.524}\times{4.184}\times{\left({65.8}-{22.0}\right)}=-{11091.6}\ {J}=-{11.09}\ {K}{J}$$
Part c)
Heat released per mole of $$\displaystyle{M}{g}={\left({\frac{{-{11091.6}}}{{{0.02156}}}}\right)}=-{514}{K}\frac{{J}}{{m}}{o}{l}$$