"Specific Heat" Help?

Question

I can't get the concept intended in my lesson for school.

Here it is:

1146 joules of heat is released when a 100.0 gram sample of an unknown metal cools from 95.00°C to 65.00°C. Determine the specific heat of a metal.

Please explain what you did, so I can get it!

Thank You in advance!

Answer 1

95.00C - 65.00C = 30.00degC difference

(1146J)/(30.00degC)(100g) = 0.382J/decC-g

Considering the units of heat capacity, you arrange the given to yield J/degC-g. What you calculate here is heat capacity, not specific heat. The two are numerically the same only in cal/degC-g. You should look up the two definitions.

Answer 2

Specific heat is the amount of energy (number of Joules) it takes to raise the temperature of 1g of a substance by 1 degC. The change in temperature was 30degrees, for a 100 g sample. That's 11.46 J to change the temperature of 1g by 30deg, or 11.46/30 = 0.382 J for every degree change in temperature per gram. Note - it's a lot easier to heat up iron than it is to heat up water, which has a specific heat of 4.18 J/g.degC.

Answer 3

Don't freak out, it's not as difficult as you might think.

The specific heat of any substance is the amount of heat required to raise the temperature of one gram of that substance 1 degree C.

To begin, let's say that since 1146 joules of heat are released when 100.0 grams of the substance cools 30 degrees, it would take the input of 1146 joules of heat to raise the temperature of that 100.0g of substance 30 degrees.

Now calculations:

(1146joules)/100.0g = 11.46 joules to raise 1 g of the substance 30 degrees.

(11.46 joules/1g)/30degrees = 0.382J/(g-C)

That's the heat required to raise 1 g of the substance 1 degree C.

Answer 4

The ewuation for specific heat is Q=c*m*delta T

Q in this specific problem is -1145j because it is released
m = 100.0g
delat T (or change in temperature) is -30.0 degrees c
always subtract final from initial.

rearang the equation to get Q/(m*delta T) = c

now you just have to plug and chug!-1146/(100*-30.0)

Answer 5

there are some topics down the line in chemistry which are pretty hard to grasp.......this aint one of 'em.
'specific heat' is short cut language for 'specific heat capacity'
just like you call the phone in your pocket a 'mobile' but its actually a 'mobile phone'.
specific heat is no more than the amount of heat needed to raise the temp of a gram of material by one degree.

if you dont specify an amount in your material, like one gram, then specific heat has no meaning and its value is infinity. but if you narrow it down to 'one gram' and just raise the temp by
'one degree', now we have a number that means something.

so just take your joules divide by 100 grams. then divide by the temp gap (95-65) and you have specific heat in
(joules)/(grams degrees c)

Answer 6

Assume constant pressure
Q=mCpdT
Cp=Q/(mdT)
Cp is kJ/(kg-K) or J/(g-K)
Get your units correct and substitute the values and solve. Answer to 4 significant figures.