[Johan]

325.0g piece of gold at 427 C is dropped into 200.0ml of water at 22.0 C. Calculate the final temperature of the mixture. Specific Heat of the Gold = .0131J/gC

So confused.. I know how to get grams of water from the equation.. but i dunno how to relate the rest of the information.

I tried setting q_H2O= q_gold but it just wont work.. i know the q from the gold is going to be negative.. but yea.. I can't calculate q individually because i can't find the change in temperature so what do i do?

[LQ43]

q_H2O= q_gold

this is a good idea

q = Cp x m x (Tf-Ti)

the Tf is what you are looking for and is the same in both q 's

1 equn 1 unknown

you know all other variables, just remember to use the correct Cp for the right m

[Johan]

Yea i'm totally stumped. I have the same equation.. I can't find q without change of temperature, nor can i find specific heat without it.. unless i'm completely missing something.

Do i ignore q and set the rest of it to zero just solving for T_f?

That doesn't seem right at all.. i need a value for q and C_p, i'm so lost please help. C_p is Heat Capacity under constant pressure isn't it? If it is.. then i really have no idea what to do.

[AlIXe]

Both substances will have the same final temperature. They will have different values of q and evidently different starting temperatures

Try:

q(Gold) = .0131J/g°C * 325 * (T(final) - 427)

q(water) = 4.186 J/g°C * 200g * (T(final) - 22)

Solve both values of q and T final by simultaneous equation
Hope this helps

[Padfoot]

Both substances will have the same final temperature. They will have different values of q and evidently different starting temperatures

Try:

q(Gold) = .0131J/g°C * 325 * (T(final) - 427)

q(water) = 4.186 J/g°C * 200g * (T(final) - 22)

Solve both values of q and T final by simultaneous equation
Hope this helps

On the right track, but Heat absorbed by water = heat lost by gold
so: q(gold)=q(water)

The 2 eqns you have above can combine - subbing in q(water) for q(gold) for example to get one eqn - with one unknown (Tfinal).

To Johan: I think this was the point LQ43 was initially making

[AlIXe]

yes, sorry i wasn't to clear, when i said different values of q i meant q(water)= - q (gold)

hope this helps