how much energy (in kJ) is required to change the temp of 1.00 kg of Fe from 25.0 degrees celsius to 1515 degrees celsius? the specific heat capacity of iron is 0.449 J/g*K.
this is the answer i got. q=(.449)(1.00)(1490)= 669.01 kJ
Good. You have improved your posting skills somewhat; you need to go further but what you have is surely a step in the right direction. Sentences should start with a capital letter. In your former posts, fe means nothing; no periods and no question marks made it difficult to interpret. You problem is not solved correctly because the units of specific heat iron and the mass of iron don't match; i.e. specific heat Fe has J/g*K but the mass Fe is listed in kg. You need to do one of two things:
a. Change specific heat to J/kg*K or
b. change mass from 1.00 kg to grams.
I suggest use your units.
q= .449J/gC*1.0kg*1490C=669kJ
There is no need to take it to five places.
Danielle--Bob Pursley just pointed out to me that you had kJ in your first post and 669 kJ is a perfectly good answer.
You guys are very intelligent!
To calculate the amount of energy required to change the temperature of a substance, you can use the specific heat capacity formula:
q = m * c * ΔT
where:
q is the amount of energy (in joules) required
m is the mass of the substance (in kilograms)
c is the specific heat capacity of the substance (in joules per gram per Kelvin)
ΔT is the change in temperature (in Kelvin)
First, convert the mass from grams to kilograms:
1.00 kg = 1000 g
Next, calculate the change in temperature:
ΔT = 1515°C - 25°C = 1490°C
To convert the change in temperature from Celsius to Kelvin, add 273.15:
ΔT = 1490°C + 273.15 = 1763.15 K
Now, plug in the values into the formula:
q = (m * c * ΔT) / 1000
q = (1000 * 0.449 * 1763.15) / 1000
= 791.56 J
Finally, convert the energy from joules to kilojoules:
791.56 J = 0.79156 kJ
Therefore, the amount of energy required to change the temperature of 1.00 kg of iron from 25.0°C to 1515°C is approximately 0.79156 kJ (or 669.01 kJ, as you calculated).