Question

Calculate the mass of Na₂CO3. aH2O required to prepare a 250 ml of a 0,05 M solution assuming that the value of a is 10.

Answer 1

3.575grams

Explanations:

From the question, we will need to determine the moles of Na₂CO3. 10H₂O using the formula below;

`moles=molarity* volume`

Given the following parameters

Molarity = 0.05M

Volume = 250ml = 0.25L

Determine the moles of Na₂CO3. 10H₂O

`\begin{gathered} moles=0.05*0.25 \\ moles=0.0125moles \end{gathered}`

Determine the Na₂CO3. 10H₂O

`\begin{gathered} Mass=moles* molar\text{ mass} \\ Mass=0.0125moles*286(g)/(mol) \\ mass=3.575grams \end{gathered}`

Hence the mass of Na₂CO3. 10H₂O required to prepare a 250 ml of a 0.05 M solution is 3.575grams