General chemistry class 121

Question

 

A lead cylinder (density=11.3 g/mL) is placed in a graduated cylinder that originally had a volume of water in it equal to 73.2 mL. After addition of the lead, the volume of the water in the cylinder reads 95.6 mL. What is the mass 

Answer 1

Density = mass/volume.

You are given the density and asked to find the mass. So, you need to find the volume. According to Archimedes Principle, the volume displaced by an object is equal to the volume of that object. So, in this problem the volume of the lead is the same as the volume of water that it displaced. That would be

95.6 ml - 73.2 ml = 22.4 ml.

Density = mass/volume

11.3 g/ml = mass/22.4 ml

mass = 11.3 g/ml x 22.4 ml = 253 g (to 3 significant figures)