billdjango99
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Ive been stuck on this question (only two marks) for a while I cant think what to do.
Can somebody tell me the steps to look at, do I need to use newtons law of cooling?

If 0.250 kg of tea with an initial temperature of 98◦C is mixed with 0.025 kg
of milk with an initial temperature of 5◦C, calculate the temperature of the resulting
mixture. Assume that the tea and the milk have the same specific heat
capacity.

Thanks for any help.
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Puddles the Monkey
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Hey - sorry you haven't had any responses so far. I'm just going to pop this in the physics study help forum for you. Hopefully someone will see this there and be able to help
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Joinedup
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(Original post by billdjango99)
Ive been stuck on this question (only two marks) for a while I cant think what to do.
Can somebody tell me the steps to look at, do I need to use newtons law of cooling?

If 0.250 kg of tea with an initial temperature of 98◦C is mixed with 0.025 kg
of milk with an initial temperature of 5◦C, calculate the temperature of the resulting
mixture. Assume that the tea and the milk have the same specific heat
capacity.

Thanks for any help.
You don't need any cooling laws

if you mixed 1kg of water at 75 degrees C and 1kg of water at 25 degrees C you'd end up with 2kg of water at 50 degrees C... right?
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billdjango99
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(Original post by Joinedup)
You don't need any cooling laws

if you mixed 1kg of water at 75 degrees C and 1kg of water at 25 degrees C you'd end up with 2kg of water at 50 degrees C... right?
Adding the masses and finding the difference of temperatures wouldn't work here though?
What formulae do I need?
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Eimmanuel
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(Original post by billdjango99)
Ive been stuck on this question (only two marks) for a while I cant think what to do.
Can somebody tell me the steps to look at, do I need to use newtons law of cooling?

If 0.250 kg of tea with an initial temperature of 98◦C is mixed with 0.025 kg
of milk with an initial temperature of 5◦C, calculate the temperature of the resulting
mixture. Assume that the tea and the milk have the same specific heat
capacity.

Thanks for any help.
(Original post by billdjango99)
Adding the masses and finding the difference of temperatures wouldn't work here though?
What formulae do I need?

You need to use conservation of energy.

Thermal energy lost by hot tea = Thermal energy gained by the “cold” milk

When the tea lost thermal energy, the temperature would drop and when the “cold” milk gained thermal energy, the temperature would rise. The tea and milk would reach an equilibrium temperature.
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billdjango99
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(Original post by Eimmanuel)
You need to use conservation of energy.

Thermal energy lost by hot tea = Thermal energy gained by the “cold” milk

When the tea lost thermal energy, the temperature would drop and when the “cold” milk gained thermal energy, the temperature would rise. The tea and milk would reach an equilibrium temperature.
Ahhh of course! Placing mc(deltaT) equal to each other! In this case the specific heat cap will cancel Thank you.
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Eimmanuel
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(Original post by billdjango99)
Ahhh of course! Placing mc(deltaT) equal to each other! In this case the specific heat cap will cancel Thank you.
Glad that you can understand and solve the problem.
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