Sciencemadness Discussion Board

Thermochemical reaction question

Locus - 26-10-2006 at 14:38

I so need this answered and no one anywhere seems to be able to.

Consider the reaction:

CaC2(s) + 2H2O(l) -->C2H2(g) + Ca(OH)2(s)

ΔH = -128.0 kJ


When 0.50 mol of CaC2 reacts with excess H2O, all the heat released from the reaction is used to heat an 8.0 kg block of iron initially at 20 degrees C. What is the final temperature of the iron block?

Specific heat of iron: 0.44 J g-1 degrees C-1.

[Edited on 26-10-2006 by Locus]

[Edited on 26-10-2006 by Locus]

Magpie - 26-10-2006 at 15:14

You seem to understand that the heat of reaction is being transfered to the iron block - right? Is it just the setting up an equation that you don't understand?

Locus - 26-10-2006 at 16:31

I guess it's the setting up of the equation for this problem that i'm not just getting.

Magpie - 26-10-2006 at 17:39

heat from reaction = heat transfered to iron block

128,000 J = (8000 g)[0.44 J/(deg C- g)](T-20 deg C)