Question

Chemistry help?!?!
A calorimeter contains 100 g of water at 25°C. You heat a 100 g copper block to its melting point (1,358 K) and plunge it in the calorimeter. Assume that the final temperature of the block reaches 25°C. How much heat was released from the copper block? At the end of the experiment, how many grams of water are liquid and at what temperature? How many grams of water are steam and at what temperature? Show your work.
Specific heat of liquid water = 4.18 J/g–°C
Specific heat of copper = 0.385 J/g–°C
ΔHv for water = 40.7 kJ/mol

Answer 1

have you tried anything?

Answer 2

No i am lost, do you know anything that could help me get the answers, could you do a step by step explanation with the answer?

Answer 3

you can start by determining the heat, q, released from the copper block.

q=mCdt

m= mass
C=specific heat capacity
dT= change in temp

Answer 4

So for water it is: 418
and for copper it is 38.5

Answer 5

what are those values of?

Answer 6

of the heat released from the water and copper, sorry im lost on this question

Answer 7

so for copper...


q=(100g)(0.385 J/g–°C)(298 K-1358K)

this was all given in the question

Answer 8

so for copper it is: -40810?

Answer 9

don't forget the units 40810 Joules

Answer 10

-

Answer 11

it's negative because energy was released

Answer 12

ok so that is the heat released from the copper block, how do you solve the other parts of the question?

Answer 13

look at this example:

Heat required to convert 100 °C water to 100 °C steam

q = m·ΔHv

where
q = heat energy
m = mass
ΔHv = heat of vaporization

q = (25 g)x(2257 J/g)
q = 56425 J

Heat required to convert 100 °C water to 100 °C steam = 56425 J

Answer 14

I think i may have got it could you tell me if I am right?

Answer 15

4.2 grams are steam at 123 degrees Celsius, 95.8 grams are liquid at 100 degrees Celsius?

Answer 16

do you have equations to go with those answers

Answer 17

I used equations to get to those answers, yes.

Answer 18

it looks like more water should be in the gas phase

Answer 19

the calculations show that only 4.2 grams are steam, what answer did you get?

Answer 20

do you know what the answer to this question is, it is really confusing: 3. Given the following equations, calculate the ΔH of reaction in which sulfur dioxide (SO2) is reduced by hydrogen disulfide (H2S) to give elemental sulfur and water (H2O).

Answer 21

Does this make any sense to you?

Answer 22

SO2 + H2S -> S(s) + H2O

balance it

then you have to do it form their enthalpies of formation

ΔH = (respective coefficients)(products)-(respective coefficients)(reactants)

Answer 23

i created an overall equation which is 2H2s+so2 Delta H 3S+2H2O
How would you use these three equations:
1.) 2H2(g)+2s(s)2H2S(g)=-41.2 kJ
2.) 2SO2 (g)2S (s)+2O2(g)=593.6 kJ
3.) 2H2+2O2(g)2H2O(g) =-571.6 kJ

Answer 24

sorry the overall equation is: 2H2s+so23S+2H2O with no delta H

Answer 25

the square boxes represent the yield

Answer 26

thats good, you have to reverse some to make it look like the one you need, then just add the individual enthalpies

Answer 27

yeah that is where i am having trouble:
would it be changing the three given: H2 (g) + S (s) → H2S (g) ΔH = –20.6 kJ
SO2 (g) → S (s) + O2 (g) ΔH = +296.8 kJ
H2 (g) + O2 (g) → H2O (g) ΔH = –285.8 kJ

to the three i tried to fo to match the target one:
1.) 2H2(g)+2s(s)2H2S(g)=-41.2 kJ
2.) 2SO2 (g)2S (s)+2O2(g)=593.6 kJ
3.) 2H2+2O2(g)2H2O(g) =-571.6 kJ

Answer 28

Not sure if i did it right

Answer 29

2H2s+so23S+2H2O


H2 (g) + S (s) → H2S (g) ΔH = –20.6 kJ (x2 and reverse)
SO2 (g) → S (s) + O2 (g) ΔH = +296.8 kJ (x2)
H2 (g) + O2 (g) → H2O (g) ΔH = –285.8 kJ (x2)

does that work out?

Answer 30

what do you mean when you say to reverse the first one?

Answer 31

for the second to that is what i did to get:
2.) 2SO2 (g)2S (s)+2O2(g)=593.6 kJ
3.) 2H2+2O2(g)2H2O(g) =-571.6 kJ

Answer 32

is that correct?

Answer 33

not sure about the first one

Answer 34

reverse it

H2S (g) →H2 (g) + S (s) ΔH = + 20.6 kJ

Answer 35

so when you add the entholpies you get: -1144.6?

Answer 36

is that correct?

Answer 37

i haven't done them myself, sorry. if you balanced the equations, that should be the right answer

Answer 38

Thanks