Percentage questions

Question 1

Lactulose can also be used to treat people who have too high a concentration of hydrogen ions (H+) in their blood.

The normal range for blood H+ concentration is 3.55 × 10–8 to 4.47 × 10–8 mol dm–3

A patient was found to have a blood H+ concentration of 2.82 × 10–7 mol dm–3

Calculate the minimum percentage decrease required to bring the patient’s blood H+ concentration into the normal range.

Answer 1

(-) 84.1(%);;

Accept (-) 84.15(%)

Allow 1 mark for

2.82 x 10-7 - 4.47 x 10-8
(divide)
2.82x10-7

Question 2

percentage decrease formula

Answer 2

original - new
(divide)
original

Question 3

percentage increase

Answer 3

final - intial
(divide)
initial