The table shows some details of the composition of inhaled and exhaled air of a student. The student is breathing 500 cm³ of air 14 times per minute. How many dm³ of oxygen will be absorbed into the lung capillaries in 4 minutes? A 0.14 dm³ B 0.35 dm³ C 1.4 dm³ D 3.5 dm³ E 35.0 dm³ F 140.0 dm³

Answer:

18) C

Volume of air inhaled in 1 minute = 500 x 14= 7000cm³ = 7dm³
Volume in 4 minutes = 7 x 4 = 28dm³
Volume of oxygen inhaled in 4 min = 0.21 x 28 = 5.88 dm³
Volume of oxygen exhaled =  0.16 x 28 = 4.48 dm³
Volume of oxygen absorbed by lung capillaries = 5.88 – 4.48 = 1.4 dm³