Question

2. Platinum metal has a density of 21.4 g/mL. If the block measures 3 cm, by 0.03 m, by 40 mm

how much does it weigh in milligrams?

Answer 1

80mg

Step-by-step explanation:

Given parameters:

Density of Platinum metal = 21.4g/mL

Dimension of the metal = 3cm by 0.03m by 40mm

Unknown:

Weight of the metal in milligrams?

Solution:

Density is the mass per unit volume of a substance.

Mathematically;

Density =
`(mass)/(volume)`

Volume of the platinum metal = l x w x h

Let us convert the dimension of the metal to the same unit;

3cm x 0.03m x 40mm

convert to cm;

100m = 1cm

0.03m =
`(0.03)/(100)` = 0.0003cm

-- 40mm;

1mm = 0.1cm

40mm = 40 x 0.1 = 4cm

Volume of the metal = 3 x 0.0003 x 4 = 0.0036cm³

1mL = 1cm³; so volume = 0.0036mL

Mass of the metal = 21.4 x 0.0036 = 0.08g

1g = 1000mg

0.08g = 0.08 x 1000 = 80mg