Select The TWO answers that are correct, Put trust in your answer brainliest
2 answers:
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Answer: the pressure exerted by the gas is 652 x 10^3 Pa, which corresponds to 652 kPa
Explanation:
The question requires us to calculate the pressure, in kPa, connsidering the following information:
<em>number of moles = n = 4.20mol</em>
<em>volume of gas = V = 15.0L</em>
<em>temperature of gas = T = 280.0 K</em>
We can use the equation of ideal gases to calculate the pressure of the gas, as shown by the rearranged equation below:
Since the volume was given in L and the question requires us to calculate the pressure in kPa, we can use R in units of L.Pa/K.mol:
<em>R = 8314.46 L.Pa/K.mol</em>
Applying the values given by the question to the rearranged equation above, we'll have:
Therefore, the pressure exerted by the gas is 652 x 10^3 Pa, which corresponds to 652 kPa.
Answer:
Option f: an addition of HCl will exceed the buffer capacity. The option d is also correct since it is a consequence of the option f.
Explanation:
The pH of the buffer solution before the addition of HCl is:
The hydrochloric acid added will react with the potassium fluoride as follows:
H₃O⁺(aq) + F⁻(aq) ⇄ HF(aq) + H₂O(l)
The number of moles (η) of potassium fluoride (KF) and the HF before the addition of HCl is:
The number of moles of the HCl added is 0.408 moles. Since the number of moles of HCl is bigger thant the number of moles of KF, the moles of HCl that remains after the reaction is:
Hence, the KF is totally consumed after the reaction with HCl and thus, exceding the buffer capacity.
We can calculate the pH after the addition of HCl:
HF(aq) + H₂O(l) ⇄ F⁻(aq) + H₃O⁺(aq) (1)
The number of moles of HF after the reaction of KF with HCl is:
And the concentration of HF after the reaction of KF with HCl is is:
Now, from the equilibrium of equation (1) we have:
(2)
By solving equation (2) for x we have:
x = 0.0187
Finally, the pH after the addition of HCl is:
Therefore, the addition of HCl will exceed the buffer capacity and thus, lower the pH by several units. The correct option is f: an addition of HCl will exceed the buffer capacity. The option d is also correct since it is a consequence of the option f.
I hope it helps you!