Question E.5: Calculating Density A man receives a ring from his fiancée, ...

Calculating Density
A man receives a ring from his fiancée, who tells him that it is made out of platinum. Before the wedding, he notices that the ring feels a little light for its size and decides to measure its density. He places the ring on a balance and finds that it has a mass of 3.15 g. He then finds that the ring displaces 0.233 cm³ of water. Is the ring made of platinum? Assume that the measurements occurred at 20°C. (Note: The volume of irregularly shaped objects is often measured by the displacement of water. In this method, the object is placed in water, and the change in volume of the water is measured. The increase in the total volume represents the volume of water displaced by the object and is equal to the volume of the object.)

Set up the problem by writing the important information that is given as well as the information that you are asked to find. In this case, you are to find the density of the ring and compare it to that of platinum.
Note: This standardized way of setting up problems is discussed in detail in Section E.8

GIVEN: m = 3.15 g
V = 0.233 cm³
FIND: density in g/cm³

Next, write down the equation that defines density.

EQUATION:  d=\frac{m}{V}