# Buffers (Worksheet)

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Section: _____________________________

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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.