50cm3 of water was heated using a methanol lamp, and the temperature rose by 20 degrees Celsius. the change in mass of methanol was 1.96 grams. the specific heat capacity of water is 4.2.
calculate the amount of energy released by 1 gram of methanol

Question

50cm3 of water was heated using a methanol lamp, and the temperature rose by 20 degrees Celsius. the change in mass of methanol was 1.96 grams. the specific heat capacity of water is 4.2. 
calculate the amount of energy released by 1 gram of methanol

jfraser · Answer

2nd law of Thermodynamics: the energy lost by the menthol must be gained by the water. Find the heat absorbed by the water$$Q(H{_2}O) = m * C * \Delta T$$ That heat must be the same as what was lost by the menthol. Divide 
$$Q(menthol) / g(menthol)$$ to find the energy per gram of menthol. I get about 2143 joules per gram

anonymous · Answer

thats what I got, but the lit value says 22.7 KJ/g

jfraser · Answer

22.7 KJ per gram? There's something wrong with that value. I can't look up an accepted value at the moment, but I'd be willing to bet that's 22.7kJ per MOLE of menthol, not per GRAM.

anonymous · Answer

per mole is 1367 kJ