Specific heat/thermal capacity

In summary, to raise the temperature of a saucepan and 5kg of water from 20 degrees Celsius to 60 degrees Celsius, a total of 100,000J of energy is required. This can be calculated using the formula Q = mcΔt, where Q is the heat energy, m is the mass, c is the specific heat capacity, and Δt is the change in temperature. For part (a), the heat energy required for the water is 100,000J and for the pan is 20,000J, giving a total of 120,000J. For part (b), the heat energy required for the water is 420,000J and for the pan is 20,000
  • #1
randomkent
8
0

Homework Statement


A saucepan of thermal capacity 500J/degC contains 5kg water at 20 degrees celcius. How much energy is required to raise the temperature of the saucepan and water:
a) to 60 degrees
b) by 60 degrees

Homework Equations


Q = mcΔt
mcΔt = mcΔt

The Attempt at a Solution


First I just did Q = 5 * 500J * 40 = 100 000J, but then I realized mcΔt = mcΔt possibly had to be used. Please help get me on the right track asap! :)
 
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  • #2
You need to know the SHC of water to calculate the heat energy required for the water.
You are given enough information to calculate the heat energy required by the pan.
 
  • #3
So would it be 2 separate answers for a, 100 000J for the water and 840 000J for the pan?
Or would it be 500*5*(60-T) = 4200*5*(60-20)
Or does the correct method derive one answer... I'm seriously lost .-.
 
  • #4
You have to calculate the total energy (pan+water) each time
500*5*(60-20) + 4200*5*(60-20) is correct for part(a)
Can you see how to do part (b)... a very subtle difference
 
  • #5
Are you sure? I was unsure about that because it doesn't account for transferred energy..
 
  • #6
Thermal capacity is not specific heat capacity
 
  • #7
Thermal capacity refers to an object, the pan needs 500J to change its temperature by 1C
Specific heat capacity refers to a substance, water needs 4200J to raise the temp of
1kg by 1C. Specific means 'per kg'
I think I have made a mistake in my previous post... the pan should be 500*(60-20)
I think that is what Vipho has picked up... SORRY... careless.
 
Last edited:

What is specific heat/thermal capacity?

Specific heat/thermal capacity is the amount of heat energy required to raise the temperature of one gram of a substance by one degree Celsius. It is a physical property of a substance that determines how much heat energy it can absorb or release when its temperature changes.

How is specific heat/thermal capacity measured?

Specific heat/thermal capacity is typically measured using a calorimeter, which is a device that can accurately measure the amount of heat entering or leaving a substance. The substance is placed in the calorimeter and its temperature change is recorded as heat is added or removed.

What factors affect the specific heat/thermal capacity of a substance?

The specific heat/thermal capacity of a substance can be affected by various factors such as its mass, molecular structure, and phase (solid, liquid, or gas). Generally, substances with higher molecular weights and more complex molecular structures have higher specific heat/thermal capacity.

Why is specific heat/thermal capacity an important concept in science?

Specific heat/thermal capacity is an important concept in science because it helps us understand how substances respond to changes in temperature. It is also crucial in various fields such as thermodynamics, engineering, and chemistry, as it allows us to calculate the amount of heat energy needed for various processes.

Can the specific heat/thermal capacity of a substance change?

Yes, the specific heat/thermal capacity of a substance can change under certain conditions. For example, when a substance undergoes a phase change (e.g. from solid to liquid), its specific heat/thermal capacity will change. Additionally, the specific heat/thermal capacity of a substance can also be affected by external factors such as pressure and temperature.

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