(1) After a certain process, the temperature changes to △t, which absorbs (or releases) heat. Q stands for heat (j),

Q=c×m×△t

Q suction = c× m× (t-t0)

Q amplifier = c× m× (t0-t)

(t0 is the initial temperature; T is the final temperature)

Where c is the specific heat capacity related to the process.

② Calculation formula of heat released by complete combustion of solid fuel: Q radiation =mq.

The calculation formula of heat released by complete combustion of gas fuel is Q=Vq.

Q stands for heat (J), Q stands for calorific value (J/kg), M stands for the mass of solid fuel (kg), and V stands for the volume of gaseous fuel (m3).

Q=Q amp/m (solid); Q=Q amp/volt (gas)

The heat released after a fuel is completely burned.

M-represents the mass of a certain fuel-kilogram.

Q-represents the calorific value of a fuel-joule per kilogram J/kg.

Unit:

The unit of heat is the same as that of work and energy. In the international system of units, the unit of heat is joule (short for coke, short for J). Historically, the unit of heat was defined as cal, which was only used as an auxiliary unit of energy. 1 Cal =4. 184 Joule.

Note: 1 kcal = 1000 kcal = 1000 calories =4 184 joules =4. 184 kj.

Detailed description of the example:

Example 1 How much heat does it take to heat 100g of water from 20℃ to 90℃? The mass of an iron nail is about 10g. How much heat will be released when cooling from 1000℃ to 25℃? [c water = 4.2×103j/(kg℃); c Fe = 0.46× 103J/(kg·℃)

Analysis: the heat absorbed by q absorbed water =c water m1(t1-t 01) = 4.2×103j/(kg℃ )× 0.1kg× (90℃-0). Heat released by nails = c Fe M2 (T02-T2) = 0.46×103j/(kg℃ )× 0.01kg× (1000℃-25℃) = 4.485×/kloc-0.

Answer: See analysis.

Fruit calories:

1, Apple100g /52 kcal

Apple is the slimming fruit that most people will choose, because it is rich in pectin, which can help gastrointestinal peristalsis and eliminate toxins in the body. Best of all, it can also reduce heat absorption. Plus apples contain a lot of potassium, which can prevent leg edema. Of course, the calories of apples are not high, so there is an apple diet meal specifically for apples.

2. Banana100g/125 kcal

Bananas are essential for many fruit diet meals, because bananas are rich in fiber, vitamin A, potassium and pectin, so they can effectively regulate the intestines and help defecate. Bananas also have the effect of removing water, which is not only the best slimming fruit, but also a beauty product, which will moisturize the skin after eating. But bananas are high in calories, and if you eat too much, you will get fat.

3. Grapefruit100g /28 kcal

Europeans and Americans like to eat acidic fruits such as grapefruit to keep fit, because acidic fruits can promote intestinal digestion. Grapefruit is rich in vitamin C, which can eliminate fatigue and make skin beautiful! Plus grapefruit has less calories and sugar content, so it is the best star fruit to lose weight.

4. Pineapple100g /32 kcal

Pineapple is also an acidic fruit, which can help the whole intestine and digestion. In addition, pineapple is rich in enzymes, which can decompose toxins and promote drainage. Therefore, it is also a fruit that people who want to be thin can eat in moderation. However, it is best not to eat pineapple before meals, because it will hurt your stomach, so you must eat something to pad your stomach before meals. Therefore, although it is delicious, you should not eat too much.

5. Kiwi100g /50 kcal

Kiwifruit is sweet and juicy and rich in vitamin C, so it has become the most popular fruit for beauty and body shaping. Sweet and sour kiwi fruit can prevent constipation, help digestion and beautify the skin. Even as a diet meal, it will make people eat with relish, and it is also a high-quality fruit with low calories and high nutrition.