Chemistry Lab, Calculated Concentration Problem. I really need help!!

Question

If there was an impurity in KHP, how would the concentration of the KHP solution differ from that calculated?

 

Would the calculated concentration of the KHP solution would be higher/lower/ or the same as (circle the correct answer) the true concentration?

explain your answer:

Answer 1

If there is an impurity in KHP, then the total mass that you have weighed is part KHP and part impurity, so you have less KHP in your sample than measured. This means that the actual number of moles of KHP in your sample is less than what you calculated.

 

If molarity = moles/L solution, the L solution stays the same, but the number of moles you actually have is less than what you calculated assuming there was no impurity. So an impure solution of KHP would have a lower concentration than what is calculated. In other words, the calculated concentration is higher than the true concentration.