Question

A student wants to measure the density of the unknown material using the displacement method.

He put 8.4 g of unknown material into the water initially at 45.4 ml, and the water level rose to 48.5 mL. What should be the correct density (g/cm3)of the unknown material from the following? 

Answer 1

Weight of the unknown = 8.4 gm

Volume of water initially $(V_1)=45.5 ml$

Final volume of water $(V_2)=48.5 ml$

So the volume of the unknown material $=V_2-V_1=48.5-45.5=3ml$

Now density:

$density=\dfrac{mass }{volume}=\dfrac{8.4}{3}=2.8 g/ml$ OR $2.8g/cm^3$