i need to know how to set up this problem for my finals, don't just post an answer please.
How could you prepare 250mL of 0.20M NaCL using only a solution of 1.0M NaCL and water.
mL x M = mL x M.
250mL x 0.20 M = mL x 1.0 M
solve for mL of 1.0 M NaCl.
Then ? mL of 1.0 M NaCl in a 250 mL volumetric flask, and make to the mark with water.
another way to think on this is that you are diluting it by 5 times, so you need four parts water and one part concentrate.
1Part=50ml 1.0M NaCl
4 parts water: 200ml
To prepare 250mL of a 0.20M NaCl solution using a solution of 1.0M NaCl and water, you can follow these steps:
Step 1: Determine the amount of moles of NaCl needed.
Since the final concentration of NaCl is given as 0.20M and the final volume is 250mL, you can use the formula:
moles of NaCl = concentration (M) x volume (L)
Converting the volume from mL to L:
moles of NaCl = 0.20 mol/L x 0.250 L
Step 2: Calculate the mass of NaCl needed.
To convert moles of NaCl to grams, you need to know the molar mass of NaCl, which is approximately 58.44 g/mol. Multiply the moles of NaCl by the molar mass:
mass of NaCl (g) = moles of NaCl x molar mass (g/mol)
Step 3: Determine the volume of the 1.0M NaCl solution needed.
The 1.0M NaCl solution contains 1.0 mole of NaCl per liter of solution. Since you need a certain amount of moles of NaCl, you can use the formula:
volume of 1.0M NaCl solution (L) = moles of NaCl needed / concentration (M)
Converting the volume from L to mL:
volume of 1.0M NaCl solution (mL) = volume of 1.0M NaCl solution (L) x 1000 mL/L
Step 4: Calculate the volume of water needed.
To get the desired final volume of 250mL, subtract the volume of the 1.0M NaCl solution from the final volume:
volume of water (mL) = final volume (mL) - volume of 1.0M NaCl solution (mL)
Step 5: Prepare the solution.
Measure the calculated volume of the 1.0M NaCl solution and pour it into a container. Then, add the calculated volume of water to the container. Ensure thorough mixing to obtain a uniform 0.20M NaCl solution.
Note: It is important to double-check your calculations and use precise measurements to ensure accurate results for your final exam.