Chemistry math conversions.

Question

The average density of human blood is 1060 kg/m³. What is the mass of blood in a person who has a blood volume of 0.00486 m³? Report your answer in units of kilograms and in units of pounds.

_____kg

_____lb

Am in need of desperate help

Answer 1

So Courtney, you will have to get used to using dimensional analysis to answer these types of questions. If you don't "get it", perhaps you can find an online video that explains it so you can do them on your own. The idea of dimensional analysis is to cancel the units you don't need, and get the answer with the desired units that you do need. A simple example would be to convert 2 feet into inches. You know that there are 12 inches in 1 foot, so you would set it up as follows so that units of feet cancel and you are left with units of inches:

2 feet x 12 inches / 1 foot =24 inches

Now for the problem at hand, we are given density of blood = 1060 kg / m³. We are asked to find the mass (kg) of 0.00486 m³ of blood. So we set up the calculation so that m³ cancel, and we are left with kg (mass).

1060 kg / m³ x 0.00486 m³ = 5.15 kg

To convert this to pounds (lb), we need to know the conversion factor between kg and lb, and that value is

1 kg = 2.2 lbs. So, we set up the conversion so that we cancel kg and end up with lbs:

5.15 kg x 2.2 lb / kg = 11.3 lb