Hi
I just need help with question (ii) and (iii), i know how to work out (i)
A solution is prepared by dissolving 0.2222 (±0.0002) g of KIO3 in 50.00 (±0.05) mL
(i) Calculate the molar mass of KIO3 with its associated uncertainty to the correct number of significant figures.
(ii) Find the molarity and its uncertainty with an appropriate number of significant figures.
(iii) Would the answer be affected significantly if the reagent were only 99.9% pure? Why or why not?
can anybody help out here
jjgyuioknj
Certainly! I can help you with questions (ii) and (iii) regarding the preparation of the solution. Let's go step by step:
(ii) To find the molarity and its uncertainty, we need to use the given mass of KIO3 and the volume of the solution.
Given:
Mass of KIO3 = 0.2222 g (with uncertainty ± 0.0002 g)
Volume of solution = 50.00 mL (with uncertainty ± 0.05 mL)
To calculate the molarity (M), we need to convert the mass of KIO3 to moles by using the molar mass of KIO3.
1. Calculate the moles of KIO3:
Moles of KIO3 = (mass of KIO3) / (molar mass of KIO3)
Now, let's calculate the molar mass of KIO3 using the given mass and the given uncertainty.
Molar mass of KIO3:
The molar mass of KIO3 is the sum of the atomic masses of potassium (K), iodine (I), and oxygen (O). By looking up the atomic masses of these elements, we find:
K: 39.10 g/mol
I: 126.90 g/mol
O: 16.00 g/mol
Therefore, the molar mass of KIO3 = (39.10 g/mol) + (126.90 g/mol) + (3 * 16.00 g/mol)
Now, let's get back to calculating the moles of KIO3 by plugging in the values:
Moles of KIO3 = (0.2222 g ± 0.0002 g) / (molar mass of KIO3)
(iii) Now, let's address the third question: Would the answer be affected significantly if the reagent were only 99.9% pure?
If the reagent is not 100% pure, it means there might be some impurities present in the KIO3 used for the solution. This can affect the accuracy of the molarity calculation.
To calculate the molarity, we assumed that the given mass of KIO3 was pure KIO3. However, if the reagent is not 100% pure, the actual mass of pure KIO3 in the sample would be less.
So, if the reagent is only 99.9% pure, it means there would be 0.1% impurities in the sample. This impurity would result in a slightly lower mass of pure KIO3 and, consequently, a lower concentration (molarity) of the solution.
Therefore, the answer would be affected to some extent because the molarity calculation assumes 100% purity of the reagent.
I hope this explanation helps! Let me know if you have any more questions.