Abomb calorimeter has a heat capacity of 2.47 kj/k. when a 0.105-g sample of ethylene (c2h4) was burned in this calorimeter, the temperature increased by 2.14 k. calculate the energy of combustion for one mole of ethylene. a. –1.41 × 103 kj/mol b. –660 kj/mol c. –5.29 kj/mol d. –0.259 kj/mol e. –50.3 kj/mol

A. –1.41 × 10³ kJ/mol

Explanation:

According to the law of conservation of energy, the sum of the heat released by the combustion and the heat absorbed by the calorimeter is zero.

Qcal + Qcomb = 0

Qcomb = -Qcal  [1]

We can calculate the heat absorbed by the calorimeter using the following equation:

Qcal = Ccal × ΔT

where,

Ccal is the heat capacity

ΔT is the change in the temperature

From [1]

Qcomb = -Qcal = -Ccal × ΔT = -2.47 kJ/K × 2.14 K = -5.29 kJ

We know that the molar mass of ethylene is 28.05 g/mol. Then, the heat released per mole of ethylene is:

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answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).