# Homework Help: [Heat and calorimeter] I can't get the correct answer

1. Jun 17, 2017

### Waffle24

1. The problem statement, all variables and given/known data
Hey there guys, first of all English is not my main language so it will be a little hard for me to say things in english. I am dutch native speaker so I will translate most of the things in english using google translator. I hope you guys are okay with that.

One wants the heat capacity of a calorimeter. It does so by one in the empty calorimeter, which has a temperature of 19.3 °C, 50 grams of benzene with a temperature of 13, 5 °C is added. This drops the temperature of the calorimeter to 15, 9 °C.
a)Calculate the value of the heat capacity of this calormeter.
b)Directly after this (the temperature of the calorimeter is still 15.9 °C), a Platinum bullet is added, which has a mass of 15.0 gram, in the calorimeter. This platinum ball has been kept in a glass flame beforehand; the temperature of the calorimeter runs to 23.7 °C . determine the temperature of the gas flame.

Now I did the same thing in b, but my answer does not match the one from my book. I tried to look if I missed any $-$ or $+$ sign , but still no luck. I even checked whether I filled the wrong number or not, and to me it seems that everything is correct. The Answer should be 604 °C , but I keep getting below 604 °C. I just want to know if I am doing something wrong or maybe the book answer could be wrong.

2. Relevant equations
$Q = m.c. \bigtriangleup T$
$Q = C .ΔT$

3. The attempt at a solution
I've uploaded 2 pictures of the calculations I did.
According to my book the answer I got for a is correct.

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2. Jun 17, 2017

### Staff: Mentor

3. Jun 17, 2017

### Waffle24

$15 × 0,13(Tend - Tbegin)$
Tend is given which = 23,7 °C
So it will be $15 × 0,13(23,7 - Tbegin)$
$15 × 0,13 = 1,95$
$1,95(23,7 - Tbegin) = 46,22 - 1,95T$

4. Jun 17, 2017

### Staff: Mentor

(468+667)/(1.95 )+ 23.7= ??

5. Jun 17, 2017

### Waffle24

Well the answer = 605,7 , but I'm still confused why you did $+ 23,7$ and not $+46,22$

6. Jun 17, 2017

### Staff: Mentor

I'm on my iPhone now, so it's hard to do equations. I'll get back with you later when I have my computer. But basically, the heat gained by the benzene and calorimeter is equal to the heat list by the bullet.

7. Jun 17, 2017

### Staff: Mentor

Heat removed from bullet = $1.95(T-23.7)$. So, $$468+667=1.95(T-23.7)$$

8. Jun 17, 2017

### Waffle24

Ah that explains it, thank you sir for your help.