Physics heat In physics of junior high school, is internal energy heat energy?

Small water droplets formed by liquefaction in cold.

There are two methods of liquefaction: reducing the temperature and compressing the volume.

Here, in the end, it is still necessary to say "liquefaction in cold condition".

The full expression is: the high-temperature water vapor does external work, the internal energy decreases, the temperature decreases, and the water vapor liquefies into small water droplets.

Note: The words "bottle mouth" will appear in the title, which means that the water vapor liquefied as soon as it rushed out of the bottle, so it is right to cool down and liquefy, but not liquefied when it encounters cold air outside.

"White mist" and "white gas" are "small water droplets" formed by the liquefaction of water vapor when it is cold.

This kind of question should be answered from a macro perspective, that is, "liquefaction in cold weather". Don't say it from a "micro perspective". This is because the internal energy is the sum of the kinetic energy and the holding energy of all molecules. The "white mist" of boiling water is part of the water molecule ......

When boiling water: when cold >> water vapor temperature decreases>> liquefifies it.

When doing work: external work, internal energy reduction, water vapor temperature reduction, liquefaction.

This question is a test of the change of matter in the second year of junior high school. It should be filled with cold liquefaction. If there is no plug in the question, its internal energy will be reduced by the temperature outside.

The internal energy consumed by pushing the plug will be transferred by the water vapor in the lower part to make up for the lost internal energy. Very little of the internal energy is consumed.

When cold, heat transfer occurs, internal energy is reduced, the temperature is reduced, and liquefaction is formed.

It should be filled with cold liquefaction formation.

It must be formed by cold liquefaction, and there is no problem of work.

Liquefaction, liquefaction of water vapor when cold.

Internal energy is the sum of the kinetic energy of the irregular thermal motion and the potential energy of the interaction between the molecules of the object.

In layman's terms, in the microscopic molecule, the molecule is always doing irregular motion, and the kinetic energy of the irregular motion of the molecule is part of the internal energy. In addition, there is an interaction force between molecules, and this interaction force provides potential energy to the molecules, which is another part of internal energy.

Thermal energy generally refers to the energy on the macroscopic level, and there is a certain transformation relationship between them. For example, in heat transfer, heat energy is absorbed, the temperature of the substance rises, the irregular movement of molecules will intensify, and the potential energy between molecules will also rise, which leads to the rise of internal energy. There are some conceptual differences between them.

First calculate the amount of heat that the aluminum pot needs to absorb when heated to 100 degrees Celsius, and then calculate the amount of heat required to heat 20 degrees of water to 100 degrees Celsius, and then add them up.

q=350080j

Q=Q1+Q2 C1M1(T-T0)=Celsius-20°C) Celsius 20°C).

Note that the quantities in the calculation problem should be calculated with units.

In addition, this is calculated according to the initial temperature of the aluminum pot is also 20 degrees Celsius, if the initial temperature of the aluminum round cavity pot is clearly stated in the problem, it should be calculated according to the initial temperature given in the potato or actual number cavity conditions.

The temperature of the aluminum is not given, and there are not enough conditions to say that the temperature of the pot and the water are the same.

There are two main points in this question, one is that the final temperature is implied by 100 degrees (given by standard air pressure), and the other is that the initial temperature of the pot is also implied. After figuring out the two key points of the imitation cluster, such as beams, you can solve them by substituting the data. I won't go into details.

:1 1:2 The specific heat capacity is the property of the substance, which is only related to the material material, and has nothing to do with the mass, so it is 1:1 by J=CMT, that is, C1M1T1=C2M2T2 substituting T1:T2=1:2

2. Waste heat of exhaust gas.

3. d The methods of changing the internal energy are work and heat transfer, and the internal energy is increased only when the ice is heated a. b Heat transfer is not considered. c No consideration is given to the work. d cooled down, did not do external work, internal energy decreased.

4. D The methods of changing internal energy include work and heat transfer, which must be something, it is wrong, and it may be something right.

5. Know the specific heat capacity of the liquid, assuming that it is c, and J=CM(T1-T2) is substituted.

m= specific heat capacity of water if the liquid is water (kg· ) Substitution. m=

The formula has been forgotten, but the idea is this, because the specific heat capacity of water is smaller than that of water. All:

The specific heat capacity of water - the specific heat capacity of copper) * 400g * (100-20) is the extra heat, knowing the extra heat, you can calculate the excess alcohol consumed (100-20) is the temperature difference.

Study hard, as a person who has come over to give you an answer, I was also in junior high school nine years ago, hehe.

Specific heat The specific heat of copper is not given.

Solution: First, find the total heat released by gasoline combustion q=mq='7j/kg='The 6J gasoline engine is done once in 4 strokes. The magnitude of each work is:

w=fs is calculated according to the pressure formula: p=f s to get f=ps=5x10'square meters ='4n(s=πr2)

w=fs=''3j: This is a work done once. But 360 revolutions per minute, of which 2 revolutions are done once. So total work ='3j='3J Finally Efficiency =w q=

360 revolutions per minute, 360 4=85 times, total work: w=fl=psl=5*10 5pa*(

Gasoline heat discharge per minute: q=mq=q=

Efficiency =w q=400350j 3220000j=

Solution: The internal energy of the water heater to convert solar energy into water in a day is equal to the heat absorbed by the water q absorption = cm (t-t0) =

q put = q suck =

From q put = mq to get m = q put q q

Solution: According to the meaning of the topic: let the heat production rate of the three units be q, and the heat transfer rate is the temperature difference between the units; Then the thermal equilibrium has:

Unit A: Q=A-B

Unit B: Q+(a-b)=b-c

Unit C: Q+(B-C)=C

The above three equations are solved together: a b=6 5; a/c=2/1=6/3

So; a:b:c=6:5:3

The answer is: d