Question

the table below shows the properties of cobalt (co) and rhodium (rh).

a scientist has a cube of solid cobalt, a cube of solid rhodium, and a cube of solid iridium. the three cubes all have the same volume. the scientist will weigh each cube and then provide the same amount of heat to each cube.

use the drop - down menus below to create two statements that describe what will happen.

the iridium cube will weigh
than each of the other two cubes.

the iridium cube will begin melting
the other two cubes.

Explanation:

Step1: Analyze the density relationship

We know that density formula is \(m =
ho V\) (where \(m\) is mass, \(
ho\) is density and \(V\) is volume). Since the three cubes have the same volume \(V\).
Given \(
ho_{Co}=8900\space kg/m^{3}\), \(
ho_{Rh} = 12450\space kg/m^{3}\). When \(V\) is constant, \(m\propto
ho\) (mass is directly proportional to density). So the iridium cube (with higher density) will have a greater mass (weigh more) than cobalt and rhodium cubes.

Step2: Analyze the melting - point relationship

Melting point is the temperature at which a solid turns into a liquid. Given \(T_{m,Co}=1495^{\circ}C\), \(T_{m,Rh}=1964^{\circ}C\). Generally, a higher - melting - point substance requires more heat (to reach its melting point) than a lower - melting - point substance. So the iridium cube (assuming its melting point is higher than cobalt and rhodium, as it is a trend in some metal groups and from the data pattern) will begin melting after the other two cubes.

Answer:

The iridium cube will weigh more than each of the other two cubes. The iridium cube will begin melting after the other two cubes.