Final answer:
The percentage error in using a buret to deliver 40.0 ml of solution into an erlenmeyer flask is approximately 0.125%.
Step-by-step explanation:
The percentage error in using a buret to deliver 40.0 ml of solution into an erlenmeyer flask can be calculated by dividing the uncertainty by the measured value and multiplying by 100. The uncertainty in each measurement is given as +/- 0.05 ml. Therefore, the percentage error can be calculated as:
Percentage error = (0.05 ml / 40.0 ml) * 100 = 0.125%
So, the percentage error in using the buret is approximately 0.125%.