№2 заполните пропуски модальными глаголами can/should/must. 1. she looks pretty sick. i think she go to a doctor. 2. you've been driving all day. you be exhausted! 3. you smoke so much. it's bad for your health. 4. hey i'm lost. you help me? 5. you have such a beautiful voice. you sing for us! 6. i know he speaks five languages, but he speak arabic? 7. that looks very expensive. it have cost a fortune! 8. i not believe that you failed your test! 9. i'm on my way. i be there in about 10 minutes. 10. i not afford that. № 3 раскройте скобки, используя условные наклонения. 1. if i hear a thief i (catch) him. 2. he would go to the cinema if he (have) more time. 3. i (phone) her yesterday if i had known her number. 4. if they were rich they (stay) at a hotel.

1:Should

2:Must

3:Should

4:Can

5:Should

6:Can

7:Must

8:Can

9:Must

10:Should

А) 1. 2Fe + 3Cl2 = 2FeCl3

2. FeCl3 + 3NaOH = Fe(OH)3 + 3NaCl

3. 2Fe(OH)3 = Fe2O3 + 3H2O

Б) 1) Fe + 2HCl = FeCl2 + H2

2. FeCl2 + 2NaOH = Fe(OH)2 + 2NaCl

3. Fe(OH)2 + 2CH3COOH = (CH3COO)2Fe + 2H2O

4. (CH3COO)2Fe + Na2S = FeS + 2CH3COONa

B) 1. 2Cu + O2 = 2CuO

2. CuO + 2HCl = CuCl2 + H2O

3. CuCl2 + 2NaOH = Cu(OH)2 + 2NaCl

4. Cu(OH)2 + H2SO4 = CuSO4 + 2H2O

5. CuSO4 + 2Na = Cu + Na2SO4

Г) 1. ZnCO3 + H2SO4 = ZnSO4 + H2O + CO2

2. ZnSO4 + 2NaOH = Zn(OH)2 + Na2SO4

3. Zn(OH)2 + 2NaOH = Na2[Zn(OH)4]

4. Na2[Zn(OH)4] + 4HCl = ZnCl2 + 2NaCl + 4H2O

С кислотой будет взаимодействовать только алюминий, так как медь в ряде напряжений металлов правее водорода

2Al + 6HCl = 2AlCl3 + 3H2

Считаем количество вещества водорода

n = V / Vm = 10.08 / 22.4 = 0.45 моль

По уравнению реакции n(Al) = 2/3n(H2) = 2/3 * 0.45 = 0.3 моль

Считаем массу алюминия

m = n * M = 0.3 * 27 = 8.1 г

Считаем массовую долю алюминия в сплаве

w = m(Al) / m(сплава) = 8.1 / 20 = 0.405 или 40.5%

Все остальное занимает медь

По уравнению реакции n(HCl) = 3n(Al) = 3 * 0.3 = 0.9 моль

Считаем массу кислоты

m = n * M = 0.9 * 36.5 = 32.85 г

ВРОДЕ ТАК) Не надейся не на кого