Question

I'm stuck on a few calculations for Heat of combustion lab. Can anyone please help me?

Answer 1

what question?

Answer 2

@aaronq

Answer 3

hm can you post it as a pdf? i don't like downloading files

Answer 4

How can I do that?

Answer 5

how about a snapshot?

Answer 6

yeah that works. as long as i don't have to download it

Answer 7

I'm not sure if you have to download it, but give me a sec. ( and I don't worry it's safe ;P)

Answer 8

haha okay.

Answer 9

Yup ; no download (:

Answer 10

I need help with 2 in Calibration of calorimeter & 3, 4 in Heat combustion of cruscose.

Answer 11

*sucrose

Answer 12

for #2, simply use the formula given \(\Delta H=C*\Delta T\)

\(\Delta H\) is given as 3226 kJ/mol

Answer 13

so 3226 kJ/mol / triangle T ?

Answer 14

yes

Answer 15

oh wait i didn't see the n

Answer 16

and to just make sure, triangle t is the answer for number one correct?

Answer 17

it's ΔH=C∗ΔT/n, so C=\(\dfrac{ΔH*n}{ΔT}\)

Answer 18

What does the n stand for?

Answer 19

moles

Answer 20

wait, whats triangle h?

Answer 21

change in Enthalpy

Answer 22

how do i find that?

Answer 23

it's given in the question

Answer 24

so .. 3226 kJ/mol * 0.008787/ 2.887 = 9.819 kj/mol ?

Answer 25

well mol is cancelling out, and you have /K

so the units should be kJ/K

Answer 26

Oh okay, but the calculations is correct?

Answer 27

yep

Answer 28

Thanks, can you show help with 3 ?

Answer 29

#3 is pretty much the same thing, just different numbers

Answer 30

and you're solving for \(\Delta H\)

Answer 31

answer for number 2 times trianlge t / moles?
x 9.819 * 2.45/ 0.002888 ?

Answer 32

ignore the x.

Answer 33

yes

Answer 34

the last part is pretty self explanatory. do you know how to do it?

Answer 35

the answer I got divided by the correct answer x 100 = the percentage of error?

8329.830/ 5639 x 100 = 147.7 % D: wut.

Answer 36

you're missing the subtraction

(8329.830-5639)/5639*100

Answer 37

47.7 % ?

Answer 38

yeah

Answer 39

Thank you so much! You're a really great helper (:!

Answer 40

thanks! and no problem at all