What is the concentration in each of the following solutions?
A) 240 mL of 0.200 M KNO3 is added to 160 mL of water.
B) 2.25g of NaCl is dissolved in 250 ml of water.
the volume has increased by a factor of 400/160. So, the concentration has decreased by the same factor.
convert grams to moles and then the concentration is moles/L
0.3
0.15
To calculate the concentration of a solution, we need to know the amount of solute (in moles or grams) and the volume of the solution (in liters or milliliters).
Let's start with the first question:
A) We have 240 mL of a 0.200 M (0.200 mol/L) solution of KNO3 added to 160 mL of water.
To calculate the concentration, we'll first find the amount of KNO3 in moles, and then divide by the total volume of the solution.
1. Convert the volumes to liters: 240 mL = 0.240 L, and 160 mL = 0.160 L.
2. Calculate the amount of KNO3 in moles: 0.240 L (solution volume) * 0.200 mol/L (concentration) = 0.048 moles of KNO3.
3. Find the total volume of the solution: 0.240 L (solution volume) + 0.160 L (water volume) = 0.400 L.
4. Calculate the concentration: 0.048 moles (amount of KNO3) / 0.400 L (total volume) = 0.120 M.
Therefore, the concentration of the KNO3 solution after adding water is 0.120 M.
Now, let's move on to the second question:
B) We have 2.25g of NaCl dissolved in 250 mL of water.
To calculate the concentration, we'll first find the amount of NaCl in moles, and then divide by the total volume of the solution.
1. Convert the volume to liters: 250 mL = 0.250 L.
2. Calculate the amount of NaCl in moles by dividing the mass by the molar mass of NaCl:
2.25 g (mass of NaCl) / 58.44 g/mol (molar mass of NaCl) = 0.0385 moles of NaCl.
3. Find the total volume of the solution: 0.250 L (solution volume).
4. Calculate the concentration: 0.0385 moles (amount of NaCl) / 0.250 L (total volume) = 0.154 M.
Therefore, the concentration of the NaCl solution is 0.154 M.