Question

How many grams of NaOH are needed to make 100 ml of a 1 M solution? (numbers only, to the nearest 0.1)

Answer 1

The mass of NaOH in grams is 4.0 grams

Step-by-step explanation

Given data

The volume of the solution = 100 ml

The molarity of the solution = 1 M

To find the mass of NaOH in grams. follow the steps below

Step 1: Find the number of moles by applying the molarity formula

`n\text{ = C}* v`

Where

n = the number of moles

C = Concentration in molarity

v = volume of the solution in liters

Step 2:convert the volume of the solution from ml to l

`\begin{gathered} \text{ 1ml is equivaent to 0.001l} \\ Hence,\text{ } \\ 100ml\text{ = 100 }*\text{ 0.001} \\ 100ml\text{ = 0.1l} \end{gathered}`

Step 3: substitute the given data into the formula in step 1

`\begin{gathered} n\text{ = cv} \\ n\text{ = 1 }*\text{ 0.1} \\ n\text{ = 0.1 mol} \end{gathered}`

Hence, the number of moles of NaOH is 0.1 mol

Step 4: Find the mass in grams by using the below formula

`\text{ Mole = }\frac{\text{ mass}}{\text{ molar mass}}`

Recall, that the molar mass of NaOH is 39.997 g/mol

Step 5: substitute the given data into the formula in step 4

`\begin{gathered} \text{ Mole = }\frac{\text{ mass}}{\text{ molar mass}} \\ 0.1\text{ = }(mass)/(39.997) \\ cross\text{ multiply} \\ mass\text{ = 0.1 }*\text{ 39.997} \\ \text{ Mass = 3.997 grams} \\ \text{ Mass}\approx\text{ 4.0 grams} \end{gathered}`

Hence, the mass of NaOH in grams is 4.0 grams