## anonymous one year ago How much heat does it take to melt 2.5 kg of lead when it is at its melting point (m.p. = 327.5ºC; ∆Hf = 2.04 * 10^4 J/kg) ? A. 6.2 × 10^1 J B. 8.2 × 10^3 J C. 5.1 × 10^4 J D. 1.7 × 10^7 J **thank you!:)

1. Michele_Laino

is \Delta H the enthalpy change?

2. anonymous

i am not sure :/ i think so... it looks like this |dw:1432830397213:dw|

3. anonymous

i did not type the subscript clearly!

4. Michele_Laino

I think that it is the fusion enthalpy change

5. anonymous

ohh okay! :)

6. Michele_Laino

so, I think that the requested amount Q of heat is given by the subsequent computation: $\Large Q = \Delta {H_f} \times m = ...Joules$

7. anonymous

okay, so i plug in like this? 2.04 * 10^4 * 2.5 ?

8. Michele_Laino

yes!

9. anonymous

yay! so we get 51000? so the answer is choice C? 5.1 * 10^4 J ?

10. Michele_Laino

that's right!

11. anonymous

yay! Thank you:D

12. Michele_Laino

Thank you!!!!! :)