Buffers (Worksheet)

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Work in groups on these problems. You should try to answer the questions without referring to your textbook. If you get stuck, try asking another group for help.

Q1

Calculate the pH of a buffer solution made from equal amounts of 0.30 M hydrofluoric acid and 0.70 M sodium fluoride. $$K_a = 7.1 \times 10^{-4}$$

Q2

Calculate the pH of a buffer solution made from 0.30 M hydrofluoric acid and 0.70 M sodium fluoride after the addition of 0.08 mol of $$NaOH$$ to 1 L of this solution. Assume no change in volume. $$K_a = 7.1 \times 10^{-4}$$

Q3

Calculate the pH of a 0.08 M $$NaOH$$ solution. Compare to the pH found in problem Q2.

Q4

What would be the buffer range for an acid if its $$K_a = 7.1 \times 10^{-4}$$ ?

Q5

Calculate the pH of a buffer solution made from 0.30 M hydrofluoric acid and 0.70 M sodium fluoride after the addition of 0.04 mol of $$HCl$$ to 1 L of this solution. Assume no change in volume. $$K_a = 7.1 \times 10^{-4}$$

Q6

Calculate the pH of a 0.04 M $$HCl$$ solution. Compare to the pH found in problem 5.