[hockey101]

Ok im trying to do a problem but the answer I came up with on my calculator is different from what my teacher got....

The Question states:  Joe heats 90 mL of water from 35 to 82.5 °C by burning 3.6 grams of hexane.  What is the heat of combustion and molar heat of combustion of this fuel? 

I know that I use this equation Q = m x ΔT x c and that 1 g = 1 ml

My Work:

(90 g) (47.5 °C) (4.184 J/ g * °C)

I know that grams and °C cancel out leaving me with Joules. 

My answer:  17886.6 J
Teacher Answer:  4275 J
Am I typing something in wrong??

*MOD Edit -- add explanatory title*

[Borek]

Teacher's answer is in cal, not J.

But neither of you solved the question so far.

[hockey101]

Thats not what my teacher said on the answer sheet and I know I have to get the first part of the equation to get the next part

[Borek]

Thats not what my teacher said on the answer sheet and I know I have to get the first part of the equation to get the next part

You can easily check by yourself:

90 (g) × 47.5 (°C) × 1 (cal g^-1°C^-1) =  4275 cal

My bet is that the teacher forgot to multiply by 4.184, and the result is in calories just because of the simple definition.

[hockey101]

Ok so then my 1st answer would be essentially correct.....17886.6