Topic content:
(6 points) (1) Chemistry is around us. The following substances are available:
a. For polyethylene, b. vitamin A, c. methane, d. sodium bicarbonate, please fill in the blanks with the serial number of corresponding substances:
① The simplest organic matter is;
② What can be used as yeast;
③ What can be used as food packaging bags;
④ Lack of night blindness;
(2) Please write the corresponding chemical symbol:
① 2 mercury atoms;
② +2 valent magnesium;
③ 2 chloride ions;
④ 2 nitrogen molecules.
(3) Fill in the blanks with the serial number. Among the following substances, those belonging to simple substances and those belonging to oxides are. What belongs to salt is, what belongs to alkali is.
A. Sulfur B. quicklime C. soda ash D. caustic soda
Best answer:
⑴①c②d③a④b⑵①2Hg②Mg③2Cl-④2N2⑶①A②B③C④D
Answer analysis:
To solve this question, we mainly examined the examples of several common substances in chemistry applied to production and life practice. Through the answer to this question, we should make it clear that chemistry originates from life, and life cannot be separated from chemistry. The key to solving this question is to fully understand the nature and use of substances. Only in this way can we make a correct judgment on the problem. It means that atoms, ions The number of molecules shall be preceded by a number; Pure substances composed of only one element are simple substances; Compounds composed of oxygen elements and another element are oxides; Compounds consisting of metal ions and acid radical ions are salts; When ionized, the generated anions are all hydroxyl ions, and the compounds are bases. Select according to the definition.
Test core:
The existence form of elements in human body:
① Carbon, hydrogen, oxygen and nitrogen mainly exist in the form of water, sugar, protein, vitamins and fat.
② Other elements mainly exist in aqueous solution in the form of inorganic salts.
③ Calcium element mainly exists in the form of hydroxycalcium phosphate [Ca10 (PO4) 6 (OH) 2] crystal.