Question

cobalt (co) is used in many engineering applications, to make specialized metal alloys and in rechargeable batteries. the density of cobalt is 8.9 g/cm³. how many moles of cobalt are there in a 1 cm³ cube of cobalt (to 2 decimal places)? o 0.07 moles of cobalt o 0.15 moles of cobalt o 0.25 moles of cobalt o 0.52 moles of cobalt cobalt 58.933 co 27

Explanation:

Step1: Calculate the mass of cobalt in 1 cm³

The density of cobalt is 8.9 g/cm³. So, the mass $m$ of cobalt in a 1 - cm³ cube is given by the density - volume relationship $m=
ho V$. Here, $
ho = 8.9$ g/cm³ and $V = 1$ cm³, so $m=8.9$ g.

Step2: Calculate the number of moles

The molar mass of cobalt (from the periodic - table information) is $M = 58.933$ g/mol. The number of moles $n$ is calculated using the formula $n=\frac{m}{M}$. Substituting $m = 8.9$ g and $M = 58.933$ g/mol, we get $n=\frac{8.9}{58.933}\approx0.15$ mol.

Answer:

0.15 moles of cobalt