Find the Molality and Molarity of a solution where 1.0g of NaCl was dissolved in 100mL of rubbing alcohol (the density of the alcohol is 0.78 g/mL).
Not sure what steps to use to find Molarity and Molality....
To find the molarity and molality of a solution, follow these steps:
1. Gather the necessary information:
- Mass of solute (in grams)
- Volume of solvent (in liters or milliliters)
- Density of the solvent (if given)
2. Convert the volume of the solvent to liters:
Given that the volume of the solvent is 100 mL, you need to convert it to liters by dividing it by 1000:
100 mL / 1000 = 0.1 L
3. Calculate the molality:
Molality (m) is defined as the moles of solute per kilogram of solvent. To calculate it, use the following formula:
Molality (m) = moles of solute / mass of solvent (in kg)
First, you need to find the moles of solute. The molar mass of NaCl is 58.44 g/mol. Therefore,
moles of NaCl = mass of NaCl / molar mass of NaCl
moles of NaCl = 1.0 g / 58.44 g/mol
Next, convert the mass of the solvent to kilograms:
mass of solvent (in kg) = volume of solvent (in L) × density of solvent (in g/mL) / 1000
mass of solvent (in kg) = 0.1 L × 0.78 g/mL / 1000
Now, you can calculate the molality:
Molality (m) = moles of NaCl / mass of solvent (in kg)
4. Calculate the molarity:
Molarity (M) is defined as the moles of solute per liter of solution. To calculate it, use the following formula:
Molarity (M) = moles of solute / volume of solution (in L)
The moles of solute and volume of solution are the same as in the molality calculation.
Now, let's calculate the molality and molarity based on the given example:
- Moles of NaCl = 1.0 g / 58.44 g/mol
- Mass of solvent (in kg) = 0.1 L × 0.78 g/mL / 1000
- Molality (m) = moles of NaCl / mass of solvent (in kg)
- Molarity (M) = moles of NaCl / volume of solution (in L)
Please substitute the calculated values to find the final results.