To 1.0 ml of 1.5%NaCl, water is added to a final volume of 100ml. What is the molarity NaCl of this final solution?
1.5g/100ml
I do not know where to go from here?
I assume that is 1.5% NaCl w/v; if so then you have 1.5g NaCl/100 mL solution. That is the same as 15g NaCl/L solution and that has a molarity of 15/58.44 = approx 0.257. So you are diluting 0.257M NaCl from 1.0 mL to 100 mL. New molarity is
M = 0.257 x (1 mL/100 mL) = ?M
To find the molarity of the final solution, you need to calculate the number of moles of NaCl present in the 1.0 ml of 1.5% NaCl solution, and then divide it by the final volume of the solution.
Let's start by calculating the number of grams of NaCl present in the 1.0 ml solution.
Given: 1.5% NaCl solution means there is 1.5 grams of NaCl in 100 ml of the solution.
To find the number of grams of NaCl in 1.0 ml of the solution, we can use proportionality:
1.5 grams / 100 ml = x grams / 1.0 ml
Cross multiplying, we get:
x = (1.5 grams / 100 ml) * 1.0 ml
x = 0.015 grams
Now that we know there are 0.015 grams of NaCl in 1.0 ml of the solution, we can find the number of moles.
The molar mass of NaCl is 58.44 g/mol. So, to calculate the number of moles, we divide the mass by the molar mass:
moles of NaCl = 0.015 grams / 58.44 g/mol
moles of NaCl = 0.000257 moles
Finally, to find the molarity of NaCl in the final solution, we divide the number of moles by the final volume of the solution:
molarity of NaCl = 0.000257 moles / 100 ml
But molarity is defined in units of moles per liter (mol/L), so we need to convert milliliters to liters by dividing by 1000:
molarity of NaCl = 0.000257 moles / 100 ml * (1 L / 1000 ml)
molarity of NaCl = 0.00000257 mol/L
Therefore, the molarity of NaCl in the final solution is 0.00000257 mol/L.