Hi,
Can someone help with the initial steps to this question?
Achieve #9 (Week 5)
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Re: Achieve #9 (Week 5)
Hey there!
It is important to note that the amount of heat gained by the water that is at 25.00 degrees C will be equal to the amount of heat lost by the water that is at 90.00 degrees C. As such, you can set an equality statement -q = q such that -q refers to that of the 25.00 degree water and q refers to that of the 90.00 degree water. Doing so will help you determine the final temperature of the water when both water sample are combined.
I hope this helps!
It is important to note that the amount of heat gained by the water that is at 25.00 degrees C will be equal to the amount of heat lost by the water that is at 90.00 degrees C. As such, you can set an equality statement -q = q such that -q refers to that of the 25.00 degree water and q refers to that of the 90.00 degree water. Doing so will help you determine the final temperature of the water when both water sample are combined.
I hope this helps!
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Re: Achieve #9 (Week 5)
hi! you use the equation mass(cold water)(C=specific heat)DeltaT(cold water) = -mass(hot water)(C)DeltaT(hot water) and then plug in the numbers given.
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Re: Achieve #9 (Week 5)
Caleb_Mei_1B wrote:Hey there!
It is important to note that the amount of heat gained by the water that is at 25.00 degrees C will be equal to the amount of heat lost by the water that is at 90.00 degrees C. As such, you can set an equality statement -q = q such that -q refers to that of the 25.00 degree water and q refers to that of the 90.00 degree water. Doing so will help you determine the final temperature of the water when both water sample are combined.
I hope this helps!
Thank you for the great explanation? Do you know if there is a specific reason why we can set q=-q for this case? Thank you in advance :)
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Re: Achieve #9 (Week 5)
That's because we're combining them together, so the heat lost by one will be gained by another, and q = -q for each.
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Re: Achieve #9 (Week 5)
Hello,
We say q = - q because one side is losing heat, while the other is gaining heat. The heat lost will be proportional to the heat gained.
We say q = - q because one side is losing heat, while the other is gaining heat. The heat lost will be proportional to the heat gained.
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Re: Achieve #9 (Week 5)
You use the following equation:
m(cold water)cΔT(cold water)=−m(hot water)cΔT(hot water)
m(cold water)cΔT(cold water)=−m(hot water)cΔT(hot water)
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Re: Achieve #9 (Week 5)
-q = q relates to the equation q(surroundings) + q(system) = 0. So, if the system is losing heat, then the surroundings would be gaining heat and vice versa. That is where you get the equation. q surroundings = -q system.
In this case, you have hot and cold water so as the hot water is transferred to the cold water heat is lost (-q). When the cold water mixes with the hot water, heat is gained (+q). You can set them equal because you are not losing any heat in this process, rather the heat is being transferred.
In this case, you have hot and cold water so as the hot water is transferred to the cold water heat is lost (-q). When the cold water mixes with the hot water, heat is gained (+q). You can set them equal because you are not losing any heat in this process, rather the heat is being transferred.
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