Find the temperature increase in C expected for 1.00 L of water when it absorbs all of the energy from the combustion of 1.00 g of acetylene, C2H2(g)? (Every mole of acetylene releases 1300 kJ of energy when combusted.)

a) 11.8C
b) 14.1C
c) 15.5C
d) 13.4C
e) 13.6C

1 Answer
Jan 25, 2018
  1. 11.8

Explanation:

Molecular weight of acetylene is (122+21) or 26gm

So, 26gm of acetylene contain 1 mol,hence 1gm contain 126 mole

Now, if per mole acetylene releases 1300KJ of energy then,for 126 moles energy released will be (13001034.2)(126) Calorie.

Now,this amount of heat(H) will be taken up by 1liter of water,

1liter=1000cm3 and density of water is 1gmcm3

So,mass of 1liter of water is 1000gm(as, mass = volume*density)

So, we can apply H=msdθ (where m is the mass of water,s is specific heat of water and its value is 1 CGS unit, and dθ is the change in temperature)

Putting the values we get, dθ = 11.9 degree C