URGENT!!
You wish to prepare 1 L of a 0.02 M potassium iodate solution. You require that the final concentration be within 1% of 0.02 M and that the concentration must be known accurately to the fourth decimal place. How would you prepare this solution? Specify the glassware you would use, the accuracy needed for the balance, and the ranges of acceptable masses of KIO3 that could be used.
(a) To make this solution (ideally) you would need ________ grams of potassium iodide dissolved in enough water to make up 1 L of solution.
fill in the blank
(b)What is the least accurate balance that could be used to make this solution?
1 - a mass spectrometer (accuracy = 0.2 µg)
2 - an electronic balance (accuracy = 2 mg)
3 - a bathroom scale (accuracy = 2 kg) 4 - a kitchen scale (accuracy = 2 g)
5 - an analytical balance (accuracy = 0.2 mg)
6 - a triple beam balance (accuracy = 20 mg)
1 L of 0.02 M = M x L = 0.02 moles
moles KIO3 = grams/molar mass
0.02 x 214.001 = ?? grams KIO3.
Ideally this is what you want. You can work out the details (I would do the percent by using +1% and -1% of 0.02 grams and recalculate).
what was the answer to the least accurate balance??
(a) To make this solution, you would need 3.132 grams of potassium iodate (KIO3) dissolved in enough water to make up 1 L of solution.
(b) The least accurate balance that could be used to make this solution is a triple beam balance (accuracy = 20 mg) (option 6).
(a) To make this solution, you would need grams of potassium iodate dissolved in enough water to make up 1 L of solution.
To calculate the mass of potassium iodate needed, we can use the formula:
Mass = Molarity * Volume * Molar mass
Given:
Molarity = 0.02 M
Volume = 1 L
The molar mass of potassium iodate (KIO3) is 214 g/mol.
Substituting these values into the formula, we have:
Mass = 0.02 M * 1 L * 214 g/mol
Simplifying, the mass of potassium iodate needed is:
Mass = 4.28 grams
Therefore, you would need 4.28 grams of potassium iodate dissolved in enough water to make up 1 L of solution.
(b) The least accurate balance that could be used to make this solution is the option 3: a bathroom scale (accuracy = 2 kg).
The accuracy of a balance is the smallest increment it can measure, or the smallest difference in mass it can detect. In this case, we require the concentration to be known accurately to the fourth decimal place, which is up to 0.0001 M. The balance used should have an accuracy equal to or better than this requirement.
Among the options given, the only balance that meets this requirement is option 5: an analytical balance (accuracy = 0.2 mg). The other options have larger inaccuracies, making them unsuitable for accurately measuring the mass of potassium iodate.