A0.1375-g sample of solid magnesium is burned in
aconstant-volume bomb calorimeter that has a heat capacity of
3,024j/oc. the temperature incresases by
1.126oc. calculate the heat given off by the burning mg,
in kj/g and inkj/mol.

a) Q = 0.025 KJ/g

b) Q = 0.602 KJ/mol

Explanation:

ΔU = Q + Wfirst law

∴ a constant volume: ΔV = 0

⇒ W = 0

⇒ ΔU = Q = CvΔT

∴ Cv = 3.024 J/°C

∴ ΔT = 1.126 °C

⇒ Q = (3.024 J/°C)×(1.126 °C ) = 3.405 J

⇒ Q = 3.405 E-3 KJ

a) Q [=] KJ/g

⇒ Q = (3.405 E-3 KJ) / (0.1375 g) = 0.025 KJ/g

b) Q [=] KJ/mol

∴ Mw Mg = 24.305 g/mol

⇒ Q = (0.025 KJ/g)×(24.305 g/mol) = 0.602 KJ/mol

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