Question

What is the concentration (M) of CH3OH in a solution prepared by dissolving 11.7 g of CH3OH in sufficient water to give exactly 100. mL of solution

Answer 1

To find the molarity of a CH₃OH solution, divide 11.7 g by the molar mass of CH₃OH (32.04 g/mol) to get moles, then divide by the volume in liters (0.1 L) to get the molarity (3.65 M).

Step-by-step explanation:

To calculate the molarity (M) of a CH₃OH solution, we use the definition of molarity which is moles of solute per liter of solution.

1. First, calculate the number of moles of CH₃OH. The molar mass of CH₃OH (methanol) is 32.04 g/mol.
   Divide the mass of CH₃OH by its molar mass to find the moles.
2. 11.7 g CH₃OH ÷ 32.04 g/mol = 0.365 moles CH₃OH
3. Next, convert the volume of the solution from milliliters to liters. 100. mL is 0.1 L.
4. Then, divide the number of moles of CH₃OH by the volume of the solution in liters.
5. 0.365 moles CH₃OH ÷ 0.1 L = 3.65 M CH₃OH

This is the concentration of the CH₃OH solution in molarity.

Answer 2

`3.65~M`

Step-by-step explanation:

We have to remember the molarity equation:

`M=(mol)/(L)`

So, we have to calculate "mol" and "L". The total volume is 100 mL. So, we can do the conversion:

`100~mL(1~L)/(1000~mL)=~0.1~L`

Now we can calculate the moles. For this we have to calculate the molar mass:

O: 16 g/mol

H: 1 g/mol

C: 12 g/mol

`(16*1)+(1*4)+(12*1)=32~g/mol`

With the molar mass value we can calculate the number of moles:

`1.7~g~of~CH_3OH(1~mol~CH_3OH)/(32~g~of~CH_3OH)=0.365~mol~CH_3OH`

Finally, we can calculate the molarity:

`M=(0.365~mol~CH_3OH)/(0.1~L)=3.65~M`

I hope it helps!