If 15.0 of is dissolved in enough water to form 270 of solution, what is the molarity of the solution?
How many milliliters of 4.45×10−2 contain 4.05 of solute
To calculate the molarity of a solution, you need to know the amount of solute (in moles) and the volume of the solution (in liters). In this case, we are given the mass of the solute and the volume of the solution in milliliters, so we need to convert the mass to moles and the volume to liters.
Here's how to calculate the molarity for the first question:
1. Convert the mass of the solute to moles:
- Since the molar mass of the solute is not provided, we cannot directly convert mass to moles. Therefore, we need to first identify the compound.
2. Once we know the compound, we can find its molar mass by adding up the atomic masses of its constituent elements.
For example, let's assume the solute is glucose (C6H12O6).
- The molar mass of carbon (C) is approximately 12.011 g/mol.
- The molar mass of hydrogen (H) is approximately 1.008 g/mol.
- The molar mass of oxygen (O) is approximately 15.999 g/mol.
By adding these up, we get:
6 * 12.011 g/mol + 12 * 1.008 g/mol + 6 * 15.999 g/mol = 180.156 g/mol (rounded to four decimal places)
Therefore, the molar mass of glucose is approximately 180.156 g/mol.
3. Convert the mass of the solute (15.0 g) to moles:
- Use the equation: moles = mass / molar mass
- moles of solute = 15.0 g / 180.156 g/mol (rounded to four decimal places)
4. Convert the volume of the solution (270 mL) to liters:
- Since 1 L = 1000 mL, divide the volume in mL by 1000 to get the volume in liters:
- volume of solution = 270 mL / 1000 = 0.270 L
5. Calculate the molarity of the solution:
- Use the equation: Molarity = moles / volume
- Molarity = moles of solute / volume of solution
Using the values calculated above, we can determine the molarity of the solution.
For the second question:
1. Convert the given mass of the solute (4.05 g) to moles, following the same steps as described above for the first question.
- Identify the solute and obtain its molar mass.
- Convert the mass to moles using the equation: moles = mass / molar mass.
2. The volume of the solution is given as 4.45×10−2 mL, which needs to be converted to liters by dividing by 1000:
- volume of solution = 4.45×10−2 mL / 1000 = 4.45×10−5 L
3. Calculate the molarity of the solution using the equation: Molarity = moles / volume.
By following these steps, you can find the molarity of a solution given the mass of the solute and the volume of the solution.