Question

Marcus measured the masses and volumes of samples of four different substances, and he calculated their densities. The table shows Marcus’s measured and calculated values. Substance Mass (g) Volume (cm3) Density (g/cm3) aluminum 5.7 2.1 2.7 copper 14.4 1.6 9.0 iron 9.5 1.2 7.9 titanium 8.6 1.8 4.8 Next, Marcus obtained another sample, which is made of one of the four substances that he had already measured. The table shows Marcus’s measured values for this unknown sample. Substance Mass (g) Volume (cm3) ? 9.5 2.1 What is the unknown sample made of?

Answer 1

Given:

Calculated density values-

Aluminum = 2.7 g/cm3

Copper = 9.0 g/cm3

Iron = 7.9 g/cm3

Titanium = 4.8 g/cm3

Unknown sample mass = 9.5 g

Sample volume = 2.1 cm3

To determine:

The identity of the unknown sample

Explanation:

'Density' is a physical parameter which can be used to identify the nature of the unknown substance.

Density = Mass/Volume

For the unknown sample

Density = 9.5 g/2.1 cm3 = 4.52 g/cm3

This matches closely with the calculated density of titanium

Ans: The unknown substance is made of titanium