A slab of granite has a mass of 1400.0 grams. The specific heat of granite is 0.040 J/gC. How much heat must be absorbed to raise the granite slab's temperature by 75 degrees C?
11.8 kJ
80.5 kJ
88.2 kJ
19.5 kJ
I've tried solving this several times and I never get one of these answers. I remembered to convert from Joules into kilojoules. Could someone help me please? What's the correct answer? Why? Is the equation 0.840J/1400.0g x 75 degrees? Why does that come out to 125 kJ?
1. D : Energy
2. B : 4.2m/s
3. C : The moon's acceleration due to gravity is less
4. C : Reference level from which the height is measured
5. D : Gravitational
6. D : All of the above
7. B : Hadron fuel cells
8. C : Relatively inexpensive and readily available
9. C : Both a and b
10. D : 78J
11. D : Thermal energy
12. B : Kinetic energy plus its potential energy
13. D : Nuclear fission and fusion reactions
14. A :The chemical energy stored in living things
15. B : Depends on the climate
16. C : Thermal energy of the object
17. C : 88.2kJ
The answer for the Thermal Energy and Matter quiz
Thanks tyler 100% correct.
heatneeded=mass*specheat*changeinT
H=1400g*.04 J/gC * 75C=4.2kJoules
which is none of the answers given.
<<Is the equation 0.840J/1400.0g x 75 degrees? Why does that come out to 125 kJ?>> That is not the equation here, at all.
Bob I'm sorry, the heat is 0.840J
The Specific Heat formula is Q = m x c x delta T. So here that would be 1400 x 0.84 x 75 = 88.2 kJ
Thanks Tyler for the 100
To calculate the heat required to raise the temperature of an object, we can use the formula:
Q = mcΔT
Where:
Q = heat absorbed or released (in joules)
m = mass of the object (in grams)
c = specific heat capacity of the material (in J/g°C)
ΔT = change in temperature (in °C)
In this case, the mass of the granite slab is given as 1400.0 grams, the specific heat of granite is 0.040 J/g°C, and the change in temperature is 75°C.
Substituting these values into the formula, we get:
Q = (1400.0 g) x (0.040 J/g°C) x (75°C)
Now, we can calculate:
Q = 1400.0 g x 0.040 J/g°C x 75°C
Q = 4200.0 J
Since the answer choices are given in kilojoules, we need to convert the answer from joules to kilojoules by dividing by 1000:
Q = 4200.0 J / 1000 = 4.2 kJ
Therefore, the correct answer is 4.2 kJ.
None of the provided answer choices match this result. Therefore, it seems there may be an error in the given answer choices or in the units used for calculation.
To summarize:
- Use the formula Q = mcΔT to calculate the heat required to raise the temperature of an object.
- Convert the mass and specific heat to consistent units (e.g., grams and joules).
- Substitute the values into the equation and calculate the result.
- Check the units and make any necessary conversions (e.g., from joules to kilojoules).