Given That The Molar Mass Of NaCl Is $58.44 \, \text{g/mol}$, What Is The Molarity Of A Solution That Contains 87.75 G Of NaCl In $500 \, \text{mL}$ Of Solution?Use The Formula For Molarity: $\text{Molarity} = \frac{\text{moles Of

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Understanding Molarity

Molarity is a fundamental concept in chemistry that measures the concentration of a solution in terms of the number of moles of a substance per liter of solution. It is a crucial parameter in various chemical reactions, and understanding how to calculate molarity is essential for chemists and students alike.

The Formula for Molarity

The formula for molarity is given by:

Molarity=moles of soluteliters of solution\text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}}

Given Values

We are given the following values:

  • Molar mass of NaCl: 58.44 g/mol58.44 \, \text{g/mol}
  • Mass of NaCl: 87.75 g87.75 \, \text{g}
  • Volume of solution: 500 mL500 \, \text{mL}

Converting Volume from Milliliters to Liters

Before we can calculate the molarity, we need to convert the volume of the solution from milliliters to liters. We know that 1 L=1000 mL1 \, \text{L} = 1000 \, \text{mL}, so we can convert 500 mL500 \, \text{mL} to liters as follows:

500 mL=5001000 L=0.5 L500 \, \text{mL} = \frac{500}{1000} \, \text{L} = 0.5 \, \text{L}

Calculating Moles of NaCl

Next, we need to calculate the number of moles of NaCl present in the solution. We can do this using the formula:

moles of solute=mass of solutemolar mass of solute\text{moles of solute} = \frac{\text{mass of solute}}{\text{molar mass of solute}}

Plugging in the given values, we get:

moles of NaCl=87.75 g58.44 g/mol=1.5 mol\text{moles of NaCl} = \frac{87.75 \, \text{g}}{58.44 \, \text{g/mol}} = 1.5 \, \text{mol}

Calculating Molarity

Now that we have the number of moles of NaCl and the volume of the solution in liters, we can calculate the molarity using the formula:

Molarity=moles of soluteliters of solution\text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}}

Plugging in the values, we get:

Molarity=1.5 mol0.5 L=3 M\text{Molarity} = \frac{1.5 \, \text{mol}}{0.5 \, \text{L}} = 3 \, \text{M}

Conclusion

In this article, we have calculated the molarity of a solution containing 87.75 g of NaCl in 500 mL of solution. We have used the formula for molarity and converted the volume of the solution from milliliters to liters. The calculated molarity is 3 M.

Common Mistakes to Avoid

When calculating molarity, it is essential to avoid common mistakes such as:

  • Not converting the volume of the solution from milliliters to liters
  • Not calculating the number of moles of the solute correctly
  • Not using the correct formula for molarity

Real-World Applications

Molarity is a crucial parameter in various chemical reactions, and understanding how to calculate molarity is essential for chemists and students alike. Some real-world applications of molarity include:

  • Calculating the concentration of a solution in a laboratory setting
  • Determining the amount of a substance required for a chemical reaction
  • Understanding the properties of a solution, such as its boiling point and freezing point

Final Thoughts

Q: What is molarity?

A: Molarity is a measure of the concentration of a solution in terms of the number of moles of a substance per liter of solution.

Q: How do I calculate molarity?

A: To calculate molarity, you need to know the number of moles of the solute and the volume of the solution in liters. You can use the formula:

Molarity=moles of soluteliters of solution\text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}}

Q: What is the difference between molarity and molality?

A: Molarity and molality are both measures of concentration, but they differ in the way they are calculated. Molarity is based on the number of moles of solute per liter of solution, while molality is based on the number of moles of solute per kilogram of solvent.

Q: How do I convert milliliters to liters?

A: To convert milliliters to liters, you can divide the number of milliliters by 1000. For example, 500 mL is equal to 0.5 L.

Q: What is the molarity of a solution that contains 25 g of NaCl in 250 mL of solution?

A: To calculate the molarity of this solution, you need to know the number of moles of NaCl and the volume of the solution in liters. First, convert the volume from milliliters to liters:

250 mL=2501000 L=0.25 L250 \, \text{mL} = \frac{250}{1000} \, \text{L} = 0.25 \, \text{L}

Next, calculate the number of moles of NaCl:

moles of NaCl=25 g58.44 g/mol=0.43 mol\text{moles of NaCl} = \frac{25 \, \text{g}}{58.44 \, \text{g/mol}} = 0.43 \, \text{mol}

Finally, calculate the molarity:

Molarity=0.43 mol0.25 L=1.72 M\text{Molarity} = \frac{0.43 \, \text{mol}}{0.25 \, \text{L}} = 1.72 \, \text{M}

Q: What is the molarity of a solution that contains 50 g of HCl in 500 mL of solution?

A: To calculate the molarity of this solution, you need to know the number of moles of HCl and the volume of the solution in liters. First, convert the volume from milliliters to liters:

500 mL=5001000 L=0.5 L500 \, \text{mL} = \frac{500}{1000} \, \text{L} = 0.5 \, \text{L}

Next, calculate the number of moles of HCl:

moles of HCl=50 g36.46 g/mol=1.37 mol\text{moles of HCl} = \frac{50 \, \text{g}}{36.46 \, \text{g/mol}} = 1.37 \, \text{mol}

Finally, calculate the molarity:

Molarity=1.37 mol0.5 L=2.74 M\text{Molarity} = \frac{1.37 \, \text{mol}}{0.5 \, \text{L}} = 2.74 \, \text{M}

Q: How do I calculate the molarity of a solution that contains a mixture of substances?

A: To calculate the molarity of a solution that contains a mixture of substances, you need to know the number of moles of each substance and the volume of the solution in liters. You can use the formula:

Molarity=moles of soluteliters of solution\text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}}

However, you need to make sure that you are using the correct formula for the specific substance. For example, if the solution contains a mixture of NaCl and HCl, you need to use the formula for each substance separately.

Q: What is the molarity of a solution that contains 100 g of glucose in 1 L of solution?

A: To calculate the molarity of this solution, you need to know the number of moles of glucose and the volume of the solution in liters. First, calculate the number of moles of glucose:

moles of glucose=100 g180.16 g/mol=0.55 mol\text{moles of glucose} = \frac{100 \, \text{g}}{180.16 \, \text{g/mol}} = 0.55 \, \text{mol}

Next, calculate the molarity:

Molarity=0.55 mol1 L=0.55 M\text{Molarity} = \frac{0.55 \, \text{mol}}{1 \, \text{L}} = 0.55 \, \text{M}

Conclusion

In this article, we have answered some frequently asked questions about molarity. We have covered topics such as the definition of molarity, how to calculate molarity, and how to convert milliliters to liters. We have also provided examples of how to calculate the molarity of a solution that contains a mixture of substances. By following the steps outlined in this article, you can calculate the molarity of a solution with ease.