really really need help w/this problem I think i figured it out but i have to be sure i did it right in order to do others similar to it

please help
thanks

Metal Specific Heat (J/g-C)
Al (s) 0.900
Au(s) 0.129
Cu(s) 0.385
Fe(s) 0.444
Hg(l) 0.139
H2O(l) 4.184
C2H5OH(l) 2.46

A piece of metal at a temp of 95.0oC and a mass of 67.0 g is dropped into a beaker of water containing 100 g at a temp. of 30.0oC. If the final temperature reached is 42.7.0oC, what is the identity of the metal?

the sum of the heats gained is zero.
heatgainedmetal+heatgainedwater=0
95*cm*(30-95)=100*4.18(42.7-30)
1.28
would it be Au?

chemistry - DrBob222, Sunday, October 24, 2010 at 10:40pm
I don't think so.
I think the 95 you have listed should be 67 g (at least from the post) and delta T for the metal is (Tfinal-Tintial). The final T from the problem is 42.7 and the initial is 95 isn't it? Check your numbers in the post. That may be a typo.

THIS IS MY REVISED ANSWER

m1*cm(T1-Tm) = m2*cw(Tm-T2)
67*cm*(95-42.7) = 100*4.18*(42.7-30)
cm = .66
What went wrong? because this isnt one of my options?

I get 1.51 which isn't on of the options either.

67X(Tfinal-Tinitial) + 100 x 4.18 x (Tfinial-Tinitial) = 0
67X(42.7-95) + 100*4.184*(42.7-30) = 0
-3504.1X + 5313.7 = 0
X = 5313.7/3504.1 = 1.52
In fact, I don't see it in this table.
http://en.wikipedia.org/wiki/Heat_capacity#Table_of_specific_heat_capacities

In your revised answer, the value of cm is 0.66. However, the specific heat values for the metals given in the problem are different. To find the specific heat of the metal, you need to rearrange the equation and solve for cm.

m1 * cm * (T1 - Tm) = m2 * cw * (Tm - T2)

Substituting the values:

67 * cm * (95 - Tm) = 100 * 4.18 * (Tm - 30)

Expanding and rearranging the equation:

67 * cm * 95 - 67 * cm * Tm = 100 * 4.18 * Tm - 100 * 4.18 * 30

Simplifying further:

6375 - 67 * cm * Tm = 418 * Tm - 12540

Rearranging the equation and collecting like terms:

(67 * cm + 418) * Tm = 12540 + 6375

Simplifying further:

(67 * cm + 418) * Tm = 18915

Now, solve for Tm:

Tm = 18915 / (67 * cm + 418)

Plug in the value of cm, which is 0.66:

Tm = 18915 / (67 * 0.66 + 418)

Tm ≈ 29

So the final temperature of the metal is approximately 29°C. Since this value is not close to any of the given temperatures in the table, it means that you made a mistake somewhere in your calculations or assumptions. I would recommend going through your calculations step by step to identify and correct any errors.