17. The atomic number of the element 3s²3p¹ : A) 12 B) 17 C) 13 D) 14 18. Potassium has the number of energy levels: A) 3 B) 5 C) 1 D) 4
19. The number of neutrons in the atom A) 17 B) 15 C) 16 D) 14
20. What mass of hydrogen gas is produced when 48 g of Mg metal reacts with sulfuric acid solution? Mg+H₂SO₄→MgSO₄+H₂
A) 2g B) 8g C) 6g D) 4g
21. The chemical reaction: 2Ca + O₂ → 2CaO is a:
A) Decomposition B) Сombination C) Single displacement D) Double displacement
22. The chemical reaction BaCl₂ + H₂SO₄ → BaSO₄ + 2HCl is a:
A) Decomposition B) Сombination C) Single displacement D) Double displacement
23. From which group and period atom with 1s² 2s² 2p⁶ 3s²
A) 2A group and 3 period B) 4A group and 3period C) 3A group and 4 period D) 2A group and 4 period
24. 96g of magnesium (Mg) was burned in oxygen gas. Calculate the mass of magnesium oxide formed. 2Mg + O₂ → 2MgO
A) 100g B) 180g C) 160g D) 140g
25. Calculate the relative density of chlorine gas (С
Объяснение:
Х г 0,1 моль
1) CuO + H2 -> Cu + H2O
n = 1 моль n=1 моль
М = 64 г/моль
m=64 г
Х г CuO - 0,1 моль Cu
64 г CuO - 1 моль Cu
m(CuO) = 64 * 0,1 / 1 = 6,4 г
40 г Х л
2) CaCO3 -> CaO + CO2
n=1 моль n=1 моль
М = 100 г/моль Vm=22,4 л/моль
m=100 г V = 22,4 л
40 г СаСО3 - Х л СО2
100 г СаСО3 - 22,4 л СО2
V(CO2) = 40 * 22,4 / 100 = 8,96 л