You are a work study student in our chemistry department. Amy, your supervisor has just asked you to prepare 500ml of 2.00M HClO4 solution for tomorrow's undergraduate experiment. The Stock Solutions cabinet is under the Stockroom Explorer. You will find find a 2.50 liter bottle containing 15M HClO4. Please prepare a flask containing 500ml of a 2.00M solution. To ensure proper credit, please write your calculations in the space given below.
In designing your procedure, it is useful to remember that diluting a substance does not change the amount of that substance. So the number of moles of the substance before the dilution is the same as the number of moles after the dilution (conservation of matter). The number of moles in solution is given by the concentration (C in moles/liter) multiplied by the volume (V in liters). So the conservation of matter implies:
C1V1 = C2V2
where C is concentration and V is volume. 1 labels the solution before the dilution and 2 labels the solution after the dilution. (This expression is based on the number of moles of the substance between the same before and after the dilution, with C (moles/liter) * V (liter) = moles).
Important: Please describe your complete procedure and the key quantities you measure. Points are based on whether or not you explain your procedure in sufficient detail for us to know what you did. You are not graded on the method you used; all approaches that produce accurate results are fine.
Well, preparing a 2.00M HClO4 solution sounds like a fun chemistry challenge! Let's get started with the procedure.
First, we have a 2.50 liter bottle containing 15M HClO4 solution. We need to calculate the volume of the concentrated solution we need to take out to prepare our desired 500ml of the 2.00M solution.
Using the formula C1V1 = C2V2, we can rearrange it to solve for V1 (the volume of the concentrated solution we need to take out):
V1 = (C2V2) / C1
Now let's plug in our values:
V1 = (2.00M * 0.500L) / 15M
Simplifying this equation, we get:
V1 = 0.0667L
So, we need to measure 66.7ml of the 15M HClO4 solution.
Next, we will transfer this measured quantity of the concentrated solution into a volumetric flask. A volumetric flask is designed to hold a precise volume of liquid, so it is ideal for preparing accurate solutions.
We will then add distilled water to the flask and carefully mix it until the solution is thoroughly mixed. Since we are diluting the concentrated solution with water, the total volume in the flask should be 500ml.
And voila! With these steps, we have prepared our 500ml of 2.00M HClO4 solution for tomorrow's undergraduate experiment.
Remember, safety is always a priority in the lab. So wear appropriate protective gear, handle chemicals with care, and follow all safety guidelines provided by your institution.
Good luck and have fun with your chemistry experiment!
To prepare a 500 ml of 2.00M HClO4 solution using the given 15M stock solution, the following steps need to be followed:
1. Calculate the volume of the stock solution required:
Using the formula C1V1 = C2V2, where C1 is the concentration of the stock solution (15M), V1 is the volume of the stock solution required, C2 is the desired concentration (2.00M), and V2 is the final volume (500 ml), we can rearrange the formula to solve for V1:
V1 = (C2 x V2) / C1
Substituting the values, we get:
V1 = (2.00M x 0.5L) / 15M
V1 = 0.067L = 67 ml
Therefore, we need 67 ml of the 15M stock solution.
2. Obtain a clean and dry measuring flask:
Select a flask with a volume slightly larger than 67 ml to ensure accuracy during the transfer.
3. Using a pipette or a graduated cylinder, measure out 67 ml of the 15M stock solution:
Be careful and accurate during the measurement to ensure the correct volume is taken.
4. Transfer the measured stock solution into the measuring flask:
Pour the 67 ml of the stock solution into the flask, making sure to transfer all of it without any spillage.
5. Add distilled water to reach the final volume:
Using a graduated cylinder or pipette, carefully add distilled water to the flask until the volume reaches the desired final volume of 500 ml.
6. Mix well:
Gently swirl or invert the flask several times to ensure proper mixing of the stock solution and water. This will help in achieving a homogeneous 2.00M HClO4 solution.
7. Label and store the prepared solution:
Label the flask with the concentration, date, and any other pertinent information. Store the solution in a safe place until it is needed for the undergraduate experiment.
It is important to note that during this procedure, accuracy in measurement and careful handling of chemicals is crucial to obtain the desired concentration. Always wear appropriate personal protective equipment (PPE) such as gloves and goggles when working with chemicals.