UnbelievableDreams one year ago I need help with Chemistry

1. Zale101

To figure out the total joules of energy from water to ice at a given temperature and mass, you do 2 calculations. The first calculation is $$\bf q=m~x~C~x~\Delta T$$ and it determines the amount of heat removed from water from18.1 °C to 0 °C for $$\bf \Delta T$$. m is mass, C is specific heat capacity. The second calculation is to use \(\bf q=m~x~H_f\ and it determines the change of state between solid to liquid. m is mass and Hf stands for the heat of fusion of water and It should be given, -335 J/g.

2. Zale101

the heat of fusion is negative 335 j/g because the liquid is freezing, going back. |dw:1436123790819:dw|

3. Zale101

Water freezes means heat is being released (negative) -335 J/g Ice melting means heat is being absorbed (positive) +335 J/g

4. UnbelievableDreams

167g x (4.184 J/g) x (0-18.1 C) = -12647 167 g x (-335 C) = -55945 -55945+ (-12647) = -68592 J Is it correct?

5. Zale101

Correct :)

6. UnbelievableDreams

It said it is incorrect. :/

7. vera_ewing

How do you know it was incorrect? Are you using the Apex Learning website?

8. UnbelievableDreams

Yes, I am using this website. I spend hours trying to solve it. Now, I have two chances. :/

9. UnbelievableDreams

I thought I was 167g, not 165g?

10. Zale101

q = 167g (4.184 J/g) (0-18.1 C) q=-12647 <-- you got this incorrect and q=167 g x (-335 C) q=-55945 Total Joules=-55945J +(-12647J)=-68592 J <--this should be the answer