1. How much heat is required to heat 1 kg of ice at --‐10 oC until it becomes 1 kg of steam at 110oC? (Be sure to show
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1. How much heat is required to heat 1 kg of ice at --‐10 oC until it becomes 1 kg of steam at 110oC? (Be sure to show
1. How much heat is required to heat 1 kg of ice at --‐10 oC until it becomes 1 kg of steam at 110oC? (Be sure to show all your work!)
2. In your own words, describe a situation where heat is transferred in each of the following mechanisms: conduction, convection, radiation.
1. How much heat is required to heat 1 kg of ice at --‐10 oC until it becomes 1 kg of steam at 110oC? (Be sure to show
1.How much heat is required to heat 1 kg of ice at --‐10 oC until it becomes 1 kg of steam at 110oC?(Be sure to show all your work!)
ANSWER:
Q=CMΔt
1kg of ice from -10°C to 0°C
Cice=2100J/(kg.℃)
Q1=2100×1×10=21000J
Cwater=4200J/(kg.℃)
Q2=4200×1×110=462000J
Q=Q1+Q2=483000J
背景知识:(一)物质有三态,即固态、液态、气态,当固态变成液态时,因溶解而吸收热量.当液态变为气态时,因蒸发而吸收热量.或由固态不经由液态,直接变成气态时,因升华而吸收热量,这些溶解、蒸发、升华过程皆会吸收热量而降低物质或空间的热量,产生冻或冷藏或冷气的效果.反之,若物质由气态变成液态时,因液化而排出热量,或由液态变为固态,因凝固而排放热量,这些液化或凝固过程皆会排放热量而提高物质或空间的温度产生加热或暖气效果.
2.In your own words,describe a situation where heat is transferred in each of the following mechanisms:conduction,convection,radiation.
ANSWER:
1 conduction is the flow of internal energy from a place of higher temperature to one of lower temperature by the interaction of the adjacent objects in the intervening space.
2 convection is the transfer of internal energy in or out of an object by the physical movement of a surrounding fluid that transfers the internal energy along with its mass.
3 radiation is the transfer of internal energy via electromagnetic waves.For most bodies on the earth,this radiation lies in the infrared region of the electromagnetic spectrum.
All the conception above shows that heat transfer can only taken from high temperature to low temperature without any work.
背景知识:热量的传递,藉由传导、对流、辐射三方式,由高温处往低温处流动,若需要将低温处之热量往高温处搬移,则需输入外力以作功,就如冷冻循环系统需由压缩机作功,将低温处之热量搬移至高温处散热.
第一题答案我不确定~上述解答仅供参考
1.将1公斤冰加热到10度再将其加热成110度的水蒸气需要多少热量?
2.用你自己的话描述热传递的情景:传导,对流,辐射。