Question

A 0.630 g sample of the ore is completely dissolved in concentrated hno3(aq). the mixture is diluted with water to a final volume of 50.00 ml. assume that all the cobalt in the ore sample is converted to co2+(aq).what is the [co2+] in the solution if the absorbance of the sample of the solution is 0.74?

Answer 1

The concentration of Co2+ in the solution is 0.05 M.

Step-by-step explanation:

To find the concentration of Co2+ in the solution, we need to use Beer's Law, which relates the absorbance of a solution to its concentration.

Beer's Law is expressed as: A = εlc, where A is the absorbance, ε is the molar absorptivity, l is the path length, and c is the concentration.

In this case, we know that the absorbance is 0.74 and the path length is 1 cm. We need to find the concentration.

First, we need to calculate the molar absorptivity (ε) using the given mass of the ore sample and the final volume of the solution. The molar absorptivity can be calculated using the formula: ε = A / (l * c).

Substituting the given values, we get: ε = 0.74 / (1 * 0.050) = 14.8 M^-1cm^-1.

Now, we can rearrange Beer's Law to solve for the concentration (c): c = A / (ε * l).

Substituting the known values, we get: c = 0.74 / (14.8 * 1) = 0.05 M.

Therefore, the concentration of Co2+ in the solution is 0.05 M.