Question

Our bodies absorb oxygen (O2) through our lungs, then distribute this oxygen to our muscles and organs. We have found that the average person has 0.0423 g O2 in their blood. 

(a) If the average person has 4.70 L of blood in their bodies, what is the concentration of oxygen (in Molarity) in the average person’s blood? (assume that blood is just water)

 

 

​(b) A person can go into shock if they lose too much blood. What mass (g) of oxygen would be lost if a person lost 0.78 L of blood?

Answer 1

(a) Molar mass of O₂ = 32 g/mol

Average mass of O₂ in blood = 0.0423 g

Moles of O₂ = $\dfrac{0.0423}{32}=1.321875\times10^{-3} mol$

Volume of Blood = 4.70 L

$\therefore$ Molarity = $\dfrac{1.321875\times10^{-3}}{4.70}\dfrac{mol}{L}$

Molarity = $2.8125\times10^{-4}mol/L$

(b) 1L of blood contains = $2.8125\times10^{-4}$ moles of O₂

0.78 L of blood contains = $2.8125\times10^{-4}\times0.78$ moles of O₂

= $2.19375\times10^{-4}$ moles of O₂

Mass of O₂ lost = $2.19375\times10^{-4}\times32$ g

= $7.02\times10^{-3}$ g