Question

no idea :( Why is ΔHf for O2 equal to zero?

Answer 1

A. Its internal energy is not equal to zero.
B. It takes a finite amount of energy to form one mole of substance.
C. It takes a finite amount of energy to produce O2.
D. O2 is already in its standard state.

Answer 2

maybe D?

Answer 3

You got it! :)

Answer 4

Look at you go! hehe

Answer 5

haha thanks!

Answer 6

No worries

Answer 7

this is D? If the ΔH for H2O(l) → H2O(s) is -6.01 kJ, then what is the ΔH for 2H2O(s) → 2H2O(l)?

A. 12.02 kJ
B. 6.01 kJ
C. -12.02 kJ
D. -6.01 kJ

Answer 8

because Delta is still the same delta

Answer 9

No, to go from liquid to solid it releases energy, but going from solid to liquid it requires energy.

Answer 10

oh i didnt even see the states

Answer 11

Whenever you have an equation in reverse, you flip the sign of the energy required.

Answer 12

got it, thanks!

Answer 13

Yeah, watch for that! No worries.