Question

A student wishes to prepare 2.00 Liters of a 0.100 M KIO3 (molecular weight 214). The proper procedure is to weigh out:_____

Answer 1

Answer:

(b) 42.8 grams of KIO3 and add H2O until the final homogeneous solution has a volume of 2.00 L

Explanation:

When calculating the amount of solid we want to weight, we only need 3 data like: total amount of solution to prepare 2,00 Liters; Solution Concentration 0,100 M KIO3 and molecular weight of the molecule KIO3, 214 g/mol.

$\frac{0.100 Moles KIO3}{L} x 2Liters x \frac{214gKIO3}{1molKIO3} = 42,8g KIO3$

Then, we take a 2 Liters Volumetric Flask, we used a funnel to let the solid slid inside the volumetric flask, then we start adding H2O until the solution is homogeneous and the meniscus aligned with the line of the flask

Answer 2

Answer:

B

Explanation:

A. Wrong

The volume of water in 2kg of water might not be 2L

D is correct.

Firstly, we need to know that the number of moles equals the mass over the molar mass. Doing this with the particular data in tie question would give 0.2M.

Hence it is essential that what we get is 0.2M in one liter. But since we are gunning for 2L, adding more than one liter of water would affect the molarity, that is why it now will be 0.1M in 2L

C is wrong

What is prepared here is 0.05M in 2L

B is wrong

What is needed is actually 2L of water and not the total volume of both being 2L

E is wrong