2HgO(s) → 2Hg(l) + O2(g) ΔH = +182 kJ HgO 25.0 g

Mercury(II) oxide decomposes to mercury and oxygen.

2HgO(s) → 2Hg(l) + O2(g) ... ΔH = +182 kJ

a. Is the reaction exothermic or endothermic?

b. How many kilojoules are needed

to react 25.0 g of mercury(II) oxide?

Ans.) a. endothermic b. 20.5 kJ

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2HgO(s) → 2Hg(l) + O2(g) ... ΔH = +182 kJ

---> HgO 2 mol 분해 시, ΔH = +182 kJ 이므로,

HgO 몰당 분해열을 계산하면,

+182 kJ / 2 mol = +91 kJ/mol

HgO의 몰질량 = 216.59 g/mol 이므로,

25.0 g HgO의 몰수를 계산하면,

25.0 g / (216.59 g/mol) = 0.1154 mol HgO

(+91 kJ/mol) × 0.1154 mol = +10.5 kJ

---> 25.0 g HgO 반응에 필요한 kJ

답: +10.5 kJ

[키워드] 2HgO(s) → 2Hg(l) + O2(g) 기준