Question

How much matter needs to be converted to energy to supply 400 kJ of energy, the approximate energy of 1 mol of C–H bonds? What conclusion does this suggest about energy changes of chemical reactions?

Answer 1

Solution:-

E = mc² .........................(1)

Where , E = energy

m = mass

c = speed of light (= 3 × 10⁸ m/ s)

E = 400 kJ = 4 × 10⁵ J (given)

Putting values of E and c , in equation (1), we get

4 × 10⁵ = m × (3 × 10⁸)²

or, m = (4 × 10⁵) / (9 × 10¹⁶) = 4.44 × 10^-12 kg

Hence, 4.44 × 10^-12 kg of matter required to be converted to energy to supply 400 kJ of energy.

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