Given :
Human blood should have around 1.04 kg/L platelets.
A blood sample of 4.01 milliliters is collected from a patient to be analyzed for a platelet count.
To Find :
The expected mass in grams of platelets in the blood sample.
Solution :
1 L of human blood contains 1.04 kg of platelets.
So, amount of platelets is 1 ml blood is :

Mass of platelets in 4.01 ml blood is :

Hence, this is the required solution.
Explanation:
The two half equations are;
3e + HNO3 → NO
S→ H2SO4 + 6e
When balancing half equations, we have to make sure the number of electrons gained is equal to the number of electrons lost.
<em>Which factor will you use for the top equation?</em>
We multiply by 2 to make the number of electrons = 6e
<em>Which factor will you use for the bottom equation?</em>
We multiply by 1 to make the number of electrons = 6e