first, thanks so much Bob for helping me!!!!

Q4.you will be asked to prepare 25.0 mL of a 0.019 M solution of sodium chloride during this experiment....

a.calculate mass of sodium chloride needed to prepare solution.

(0.25L)(0.019M NaCl/L)*(58.5g NaCl/1mole NaCl)=0.278 g NaCl....is that correct? if not how should I go about finding the answer??

b.youre given 25mL volumetric flask. Describe the procedure you will follow in lab to prepare the solution in Question4a.

i don't know...i'm really bad at lab question...

c.you add 4.0mL of the NaCl solution from Q4a to a clean 25mL volumetric flask and dilute it to exactly 25.0mL. What is the concentration of the dilute solution?

help???

i think 2.3 mL of naCI/L hydrocholric acid

for part a? and how did you get that? thanks.

25 mL = .025 L, not .25L

a. To calculate the mass of sodium chloride needed to prepare the solution, you can use the formula:

Mass = Volume (in liters) * Concentration * Molar Mass

In this case, the volume is given as 25.0 mL, but it is usually easier to work with liters, so you need to convert it to liters. Since there are 1000 mL in a liter, 25.0 mL is equal to 0.025 L.

The concentration is given as 0.019 M.

The molar mass of sodium chloride (NaCl) is 58.5 g/mol.

Putting these values into the formula, we get:

Mass = 0.025 L * 0.019 M * 58.5 g/mol = 0.278 g

So, your calculation of 0.278 g NaCl is correct.

b. To prepare the solution in a 25 mL volumetric flask, you would follow these steps:

1. Weigh out the required mass of sodium chloride, which is 0.278 g as calculated in the previous step.

2. Add the sodium chloride to a clean container, such as a beaker.

3. Add a small amount of distilled water to the beaker to dissolve the sodium chloride.

4. Transfer the dissolved sodium chloride solution to a 25 mL volumetric flask using a funnel or pipette.

5. Rinse the beaker and the funnel or pipette with distilled water to ensure all the sodium chloride is transferred to the volumetric flask.

6. Fill the volumetric flask slowly with distilled water until the meniscus of the solution is at the calibration mark on the neck of the flask. Avoid air bubbles.

7. Cap the volumetric flask and invert it several times to ensure thorough mixing of the solution.

c. For this question, you are adding 4.0 mL of the NaCl solution prepared in question 4a to a clean 25 mL volumetric flask and diluting it to exactly 25.0 mL. The concentration of the dilute solution can be calculated using the formula:

Concentration = (Volume of initial solution * Concentration of initial solution) / Final volume

In this case:
- The volume of the initial solution is 4.0 mL.
- The concentration of the initial solution is 0.019 M.
- The final volume is 25.0 mL.

Plugging these values into the formula:

Concentration = (4.0 mL * 0.019 M) / 25.0 mL

Simplifying the equation:

Concentration = 0.00304 M

So, the concentration of the dilute solution is 0.00304 M.