Question

How much heat (kJ) is needed to raise the temperature of 100.0 grams of water from 25.0ºC to 50.0ºC?

Answer 1

Hello!

Answer 2

I already worked the problem, however I seem to be a little confused with what the answer should be. I'll show you the steps.

Answer 3

q= m * c * delta(T)
q= 100 * 4.18 j/g º C * 50ºC - 25ºC
q=10450

Answer 4

q=mct
Where q is heat transferred
m is the gram of substance
c is the specific heat capacity. For water is it 4.18J/g*K
t is temperature in Kelvin.
Formula for Kelvin is
K=C+273.15

Answer 5

My answer choices are this
A) 10450
B) 0.598
C) 1.05
D) 10.5
E) none of the above

Answer 6

T is temperature difference between the 2 Kelvins temperature

Answer 7

Yep, you did it correctly!

Answer 8

My issue is I'm not sure if i have to leave the answer as 10450 or do i have to make it according to the sig figs?

Answer 9

for example the lowest sigfig is 3 so would i leave it as 10450 or 105?

Answer 10

It would be 1.05 x 10^4 J
You need to use scientific notation

Answer 11

That makes it 3 sf also.

Answer 12

Is it require for every answer to use scientific notation?

Answer 13

No, only if lowest sf is lower than the whole number's sf
Like lowest sf is 4 and answer is 102345.23 or 102345
It would be 1.023 x 10^5

Answer 14

Okay so in my case i got the answer 10450. I need to get it to 3 sf because its the lowest in the problem. I would make it 1.045 but round it to 1.05 making it 1.05 x 10^4?

Answer 15

To make it 3 sf, you round out the 5 to make it gone.

Answer 16

Right. So my choices are these
A) 10450
B) 0.598
C) 1.05
D) 10.5
E) none of the above

Answer 17

would the answer be C?

Answer 18

However there isn't a "x 10^4" or does it make it e?

Answer 19

You need the scientific notation.
So what do you think the answer is now?

Answer 20

1.05 does not equal 10450 or 10500
but 1.05 x10^4 does.

Answer 21

I think it's E

Answer 22

Yes, it would be because the answers are not in correct sf.

Answer 23

Thanks a lot!