محلول، توازن اور حرکیات

Written by Dr. Ayesha Nadeem (Chemistry)

نیٹ · کیمیا · 8 سوالات

نام: ____________________ تاریخ: ____________

How many atoms are there in exactly 12 g of carbon-12?
- A 6.022 x 10^22
- B 12 x 6.022 x 10^23
- C 3.011 x 10^23
- D 6.022 x 10^23
What is the molarity of a solution containing 98 g of H2SO4 in 1 litre of solution? (H = 1, S = 32, O = 16)
- A 1 M
- B 98 M
- C 2 M
- D 0.5 M
The elevation of the boiling point of a solution is proportional to its:
- A Colour
- B Volume
- C Molality
- D Density
For N2 + 3H2 <-> 2NH3, the relation Kp = Kc (RT)^n has n equal to:
- A 2
- B 4
- C -2
- D -4
The forward reaction of an equilibrium is exothermic. Raising the temperature will:
- A Have no effect on the equilibrium
- B Double the equilibrium constant
- C Shift the equilibrium to the left
- D Shift the equilibrium to the right
For a first order reaction, doubling the concentration of the reactant makes the rate:
- A Four times as large
- B Halve
- C Double
- D Stay the same
What is the pH of 0.1 M NaOH at 25 degrees C?
- A 12
- B 13
- C 1
- D 14
Which of these is a Lewis acid?
- A NH3
- B BF3
- C H2O
- D OH-

جوابی کلید

1. D, 2. A, 3. C, 4. C, 5. C, 6. C, 7. B, 8. B

12 g of carbon-12 is one mole, which contains Avogadro's number of atoms, 6.022 x 10^23.
The molar mass of H2SO4 is 98 g/mol, so 98 g is 1 mole. In 1 litre this is 1 M.
Boiling point elevation is a colligative property: delta Tb = Kb x molality.
n is the change in moles of gas: 2 - (1 + 3) = -2.
According to Le Chatelier's principle, the system opposes the added heat by favouring the endothermic, reverse reaction.
Rate = k[A], so the rate is directly proportional to concentration.
[OH-] = 0.1, so pOH = 1 and pH = 14 - 1 = 13.
BF3 has an empty orbital on boron and accepts an electron pair, so it is a Lewis acid.