(1)① The main component of salt is sodium chloride, the main component of vinegar is acetic acid, the main component of cooking wine is alcohol, soda refers to sodium carbonate, and the main component of charcoal is carbon, which is a pure substance composed of the same elements, including metal and nonmetal elements, and iron and charcoal belong to metal and nonmetal elements respectively; Compounds are pure substances composed of different elements. Sodium chloride, sodium carbonate, water, acetic acid and alcohol are all compounds. Oxide refers to a compound composed of two elements, one of which is oxygen and water meets the definition; Salt refers to a compound composed of metal ions and acid radical ions, and sodium chloride and sodium carbonate meet the definition; Organic matter refers to carbon-containing compounds (except carbon oxides, carbonic acid and carbonate), and acetic acid and alcohol meet the definition.
(2) Vinegar contains acetic acid, and alumina reacts with acetic acid to produce aluminum acetate and water. The equation is Al _ 2O _ 3+6HAC = 2Alac _ 3+3H2O; Aluminum reacts with acetic acid to produce aluminum acetate and hydrogen, and the equation is 2Al+6HAc=2AlAc 3 +3H 2 ↑.
(2)① According to the composition and properties of pig iron and the properties of aluminum, the following contents can be filled in:
Advantages and disadvantages of kinds
For example, copper pot has good thermal conductivity and high cost, and copper rust is harmful to human body.
Iron pots are low in cost (iron can be supplemented) and easy to rust.
Aluminum pot is light (not easy to rust). Aluminum ions are harmful to human health. (2) Alloy refers to a mixture with metallic characteristics formed by heating and melting some metals or nonmetals in metals. Stainless steel is a mixture of iron and a small amount of carbon, which is an iron alloy. Compared with pig iron, its biggest advantage is that it is not easy to rust
③ Organic polymer synthetic materials mainly include plastics, synthetic fibers and synthetic rubber, and Teflon is a special kind of plastic.
(4) the stronger the metal activity, the easier it is to form compounds, the easier it is to exist in a combined state, and the more difficult it is to form simple substances, so the stronger the metal activity, the more difficult it is to smelt.
⑤ Reducing iron oxide with carbon monoxide means that carbon monoxide reacts with iron oxide at high temperature to generate iron and carbon dioxide, and the equation is Fe 2 O 3 +3CO.
high-temperature
.
2Fe+3CO 2。
(3)① Six nutrients in human body include sugar, oil, protein, vitamins, water and inorganic salts;
A, roast chicken wings mainly contain protein and oil, so it is wrong; B, pure milk mainly contains protein, so it is wrong; C, rice mainly contains sugar, so it is correct; D, mixed cucumber mainly contains vitamins, so it is wrong.
Steamed bread mainly contains sugar, braised beef mainly contains protein, oil and a small amount of inorganic salts, peanuts mainly contain protein and oil, steamed fish mainly contains protein, beverage cola mainly contains water and inorganic salts, and vitamins mainly exist in vegetables and fruits, so the complementary food is mixed cucumber.
A, iron is the main element in the synthesis of hemoglobin, lack of which will lead to anemia, so it is wrong.
B, selenium can prevent cancer. Selenium deficiency can cause keratinization and canceration of epidermis, so it is wrong.
C, calcium mainly exists in bones and teeth, so that bones and teeth have a hard structural support. Lack of children and adolescents will suffer from rickets, and the elderly will suffer from osteoporosis, so it is wrong.
D, zinc affects people's development, zinc deficiency can cause loss of appetite, growth retardation and dysplasia, so it is correct.
② a. protein is decomposed into amino acids under the action of protease and water. Some of them are oxidized by oxygen to CO 2, CO(NH 2) 2 (urea) and H 2 O. These products contain four elements: carbon, hydrogen, nitrogen and oxygen. According to the law of conservation of mass, protein also contains these four elements. After protein enters the human body, it reacts with water under the action of protease to hydrolyze into amino acids, which must contain amino acids.
B Every 100g of milk powder contains protein =100g * 2% ÷16% =12.5g, so the milk powder is unqualified.
So the answer is: (1)①.
②al2o 3+6 HAC = 2 alac 3+3h2o； 2Al+6 HAC = 2 alac 3+3H 2↑； (2)①
Advantages and disadvantages of kinds
For example, copper pot has good thermal conductivity and high cost, and copper rust is harmful to human body.
Iron pots are low in cost (iron can be supplemented) and easy to rust.
Aluminum pot is light (not easy to rust). Aluminum ions are harmful to human body. Alloy; Not easy to rust; ③ Organic synthetic polymer materials; ④B； The more active the metal is, the more difficult it is to smelt; ⑤Fe 2 O 3 +3CO
high-temperature
.
2Fe+3CO 2； (3)① vitamins; CDD； ② Communication, communication, communication, communication;
B Every 100g of milk powder contains protein =100g * 2% ÷16% =12.5g, so the milk powder is unqualified.
2. Chemistry in the kitchen
Chemistry in the kitchen, as we all know, people absorb nutrition by digesting food. The digestion process of food is a series of complex chemical reaction processes, and the speed of chemical reaction has a great relationship with the surface area of reactants, humidity during the reaction and catalysts.
Protein, fat and starch in food are insoluble in water, which brings difficulties to people's digestion and absorption. After food is cooked, it absorbs water, expands and splits when heated, and some of it becomes water-soluble substances, which are easily catalyzed by enzymes in the gastrointestinal tract and absorbed by the human body. For example, starch particles are insoluble in cold water, but they will be absorbed, swollen, broken and turned into paste in warm water, and then react with water to turn very large starch molecules into many small molecules-oligosaccharides and monosaccharides.
Rice, noodles and other staple foods contain a lot of starch, which is easily absorbed by the digestive system of the human body after cooking. Cooking is both a science and an art.
A pile of lettuce, after being boiled, fried, boiled and stuffy, has become a dish with good color and flavor, which is inseparable from the chef's skills and contains a lot of chemical knowledge. For example, in cooking, the order of adding condiments is sequential, not based on the operator's interest, otherwise the color, aroma and taste will be affected.
The order of adding condiments depends on the penetration strength. Strong permeability is strong after.
When cooking, put sugar first, then add salt, vinegar, soy sauce and monosodium glutamate. If the order is reversed, put salt first, which will hinder the diffusion of sugar. Because salt has dehydration effect, it will promote protein solidification, make the surface of food hard and tough, and the sweetness of sugar is difficult to penetrate.
There are also individual principles, that is, odorless spices (such as salt and sugar) can be heated for a long time when cooking, while scented spices can't, so as to avoid the fragrance escaping. The main component of monosodium glutamate is sodium glutamate, which can't stand the high temperature of cooking and can only be added at the end. ? When cooking food, the time of adding seasoning is also related to the chemical changes in food.
Protein in food itself has the nature of colloid, which will condense when it meets strong electrolytes such as sodium chloride. For example, soy milk with salt will condense into tofu brain. If salt is added too early when cooking beans and burning meat, there is salt in the noodle soup, so it is difficult for water to penetrate into beans or meat; On the other hand, salt can make protein in beans or meat coagulate and harden.
These two aspects make it difficult to cook beans or meat, and of course it is not conducive to human digestion and absorption. ? The cooking temperature of food, that is, temperature, has a great influence on food.
Generally speaking, increasing the temperature can speed up the reaction. For example, the temperature of stewing food is about 100 degrees (boiling point of water), and the temperature of frying is about 200 to 300 degrees (boiling point of oil is higher than water). The frying temperature is slightly lower than that of frying, but much higher than that of stewing.
Therefore, it takes several times more time to cook and simmer the meat than to fry it, and the temperature in the pot is also related to mixing and frying. Stir-frying can make food heated evenly, but excessive stir-frying will reduce the temperature in the pot, increase the chance of food contacting with oxygen in the air, and make vitamin C in food easy to be destroyed by oxidation.
Therefore, the pot cover must be added after cooking. First, it can prevent the pot temperature from decreasing. Second, it can prevent vitamin oxidation and reduce nutritional value. ? Many families like to add some wine when cooking fish. What do you think this is? There is more trimethylamine in dead fish, so the longer the fish dies, the stronger the smell.
Trimethylamine is insoluble in water and soluble in alcohol, so adding wine when cooking fish can remove the fishy smell and make the fish taste better. Wine can remove the fishy smell of fish and meat; The role of wine is not limited to this. When cooking, the fat in food will be partially hydrolyzed to produce acid and alcohol.
When wine (containing ethanol), vinegar (containing acetic acid) and other seasoning accessories are added, acid and alcohol undergo esterification reaction to form aromatic esters. ? Chemistry is everywhere in the kitchen. For example, liquefied gas is a mixture of some lower hydrocarbons, and the small molecules of hydrocarbons-oligosaccharides and monosaccharides.
Rice, noodles and other staple foods contain a lot of starch, which is easily absorbed by the digestive system of the human body after cooking. Exploring Chemical Reactions in the Kitchen For housewives, the kitchen is a small world.
Every family has a kitchen, but the chemical knowledge involved in the kitchen can be seen everywhere. For example, what if the oil pan catches fire? How to deal with gas leakage? How to treat domestic sewage? Most of our kitchens have: wine, vinegar, running water, salt, eggs and so on.
The main component of vinegar is acetic acid (CH3COOH), and its chemical name is acetic acid. Acetic acid can only ionize hydrogen ions (H+) and acetate ions (CH3COOO—-) in water, and can also be replaced by active metals to reflect the generation of hydrogen, so household aluminum products should not be used for vinegar to avoid corrosion. Have you noticed? When cooking bone soup, parents will add a small amount of vinegar to the soup. Why? Because bone contains calcium phosphate, which is insoluble in water, calcium phosphate reacts with acetic acid to produce water-soluble calcium dihydrogen phosphate, which can increase the calcium content in soup and is beneficial to the growth of students.
In the kitchen, the daily necessary procedures include washing food, so the daily water consumption is very large, and countless sewage is discharged every day. However, many countries and regions are short of fresh water resources, and how to solve the water problem is the focus of discussion today.
Since we can't dig out new sources of fresh water, can we start with saving water? How can we reuse domestic sewage? How to remove the residue and odor in broken vegetable leaves, sediment and sodium chloride? To remove the broken vegetable leaves and sludge in sewage, relatively pure water can be obtained by filtration. Dissolution and filtration are carried out in two steps, and then the odor of sewage can be removed by adsorption of activated carbon. The water obtained after a round of treatment can be used as toilet cleaning water or watering flowers and grass. In this resource-poor environment, sewage reuse can reduce sewage discharge, reduce water pollution, save water resources and reduce the cost of domestic water. Turn waste into treasure. We can also do some interesting laboratory tests through kitchen supplies, such as making "egg-free eggs". When an egg is placed in a glass tube filled with vinegar, it will sink to the bottom of the tube, generating bubbles on its surface and rising slowly. Because the eggshell is CaCO3, CaCO3 +2HCl=.