The meaning of 2 in c2h6o is () A. There are two carbon atoms in alcohol, B. two carbon atoms C. Alcohol contains two carbon elements D. each alcohol molecule contains two carbon atoms 4. The correct statement about "1,2,3,4" of 4h2co3 is () A. 2 represents two hydrogen atoms in carbonic acid and 3 represents three oxygen elements in H2CO3 molecule C. 4 represents the number of molecules, and D.1 represents that each H2CO3 molecule has a sulfate radical 5. In the following symbols, () A.H B.O2 C.He D.NaCl 6. In water (H2O) and sulfuric acid (H2SO4), it contains () A. The same number of hydrogen molecules B. the same number of hydrogen elements C. the same number of hydrogen atoms D. hydrogen elements 7. The mistake in the following statement is () A. The valence of an atomic group must not be zero. B. some elements have variable valence C. The valence of elements in the simple substance is zero D. nonmetallic elements always show negative valence 8. Among the following substances, those without atomic groups are () A、MgCl2 B、NaNO3 C、Ca(OH)2 D、NH4Cl 9. In chemical terms: (1) Five nitrogen atoms___________ (2) Two hydrogen molecules (3) Three magnesium ions (4) Two hydroxyl ions_______ (5) The most abundant substance in the air (6) Four aluminum ions (7) Hexavalent sulfur________ (8) The smallest particle that maintains the chemical properties of water_____________ . (9) The valence of oxygen in hydrogen peroxide is negative________ (10) Lack of it can lead to thyroid disease 10. The meaning of the value "2" in the following formula is pointed out ⑴2O ⑵O2 ⑶O2- ⑷ H2SO4 ⑸2N2 、 (6)2Mg

The meaning of 2 in c2h6o is () A. There are two carbon atoms in alcohol, B. two carbon atoms C. Alcohol contains two carbon elements D. each alcohol molecule contains two carbon atoms 4. The correct statement about "1,2,3,4" of 4h2co3 is () A. 2 represents two hydrogen atoms in carbonic acid and 3 represents three oxygen elements in H2CO3 molecule C. 4 represents the number of molecules, and D.1 represents that each H2CO3 molecule has a sulfate radical 5. In the following symbols, () A.H B.O2 C.He D.NaCl 6. In water (H2O) and sulfuric acid (H2SO4), it contains () A. The same number of hydrogen molecules B. the same number of hydrogen elements C. the same number of hydrogen atoms D. hydrogen elements 7. The mistake in the following statement is () A. The valence of an atomic group must not be zero. B. some elements have variable valence C. The valence of elements in the simple substance is zero D. nonmetallic elements always show negative valence 8. Among the following substances, those without atomic groups are () A、MgCl2 B、NaNO3 C、Ca(OH)2 D、NH4Cl 9. In chemical terms: (1) Five nitrogen atoms___________ (2) Two hydrogen molecules (3) Three magnesium ions (4) Two hydroxyl ions_______ (5) The most abundant substance in the air (6) Four aluminum ions (7) Hexavalent sulfur________ (8) The smallest particle that maintains the chemical properties of water_____________ . (9) The valence of oxygen in hydrogen peroxide is negative________ (10) Lack of it can lead to thyroid disease 10. The meaning of the value "2" in the following formula is pointed out ⑴2O ⑵O2 ⑶O2- ⑷ H2SO4 ⑸2N2 、 (6)2Mg

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What is the principle of removing water from industrial alcohol?

First add quicklime, then distill: Cao + H2O = Ca (OH) 2

When the chemical formula of alcohol is C2H5OH, the mass fraction of oxygen in 100 g 46% alcohol solution is the ratio of alcohol molecules to water molecules

C2H5OH is recorded as c2h6o for convenience
First calculate the quality of pure alcohol: 100g * 46% = 46g
Then calculate the mass fraction of oxygen in alcohol: 16 * 1 / 12 * 2 + 6 * 1 + 16 * 1 = 34.8%
Mass fraction of oxygen in 100g alcohol: 46g * 34.8% / 100 = 16.008%
Number ratio of alcohol to water: n alcohol: 46g / (12 * 2 + 6 * 1 + 16) g / mol = 1mol
N water: 100g-46g / 18G / mol = 3Mo;
N alcohol: n water = 1:3
Mass fraction of oxygen in 100g alcohol: 46g * 34.8% / 100 = 16.008%
N alcohol: n water = 1:3