Question

During the phosphatase experiment you will use a 1% w/v of phenolphthalein di-phosphate (PPP). How much PPP do you need to make 500ml of the solution if you only have 25g and you know that the MW of PPP is 478 g/mole?

Answer 1

To prepare a 1% w/v solution of phenolphthalein di-phosphate (PPP) for 500ml, you need to weigh out 5 grams of PPP and dissolve it in enough water to make the total solution volume up to 500 ml.

Step-by-step explanation:

To prepare a 1% w/v solution of phenolphthalein di-phosphate (PPP) for 500ml, you first need to understand that 1% w/v means you have 1 gram of solute for every 100 milliliters of solution. Then, for 500 milliliters, you would need 5 grams of PPP. The molar mass of PPP (478 g/mol) is only used to calculate moles from grams or vice versa and is not needed to prepare a percent weight/volume solution. Since you have enough PPP (25g), you can weigh out 5 grams of PPP and dissolve it in water to make a total volume of 500ml to achieve a 1% w/v concentration.

Steps to prepare the solution:

1. Calculate the total amount of PPP needed: 500 ml * 1%/100ml = 5 grams.
2. Weigh out 5 grams of PPP.
3. Dissolve the PPP in a volume of water less than 500 ml.
4. After PPP has dissolved, adjust the solution volume to 500 ml with water.

Answer 2

To make 500 mL of a solution of PPP 1% w/v you need 5g

Step-by-step explanation:

A percent w/v solution is calculated with the following formula using the gram as the base measure of weight (w):

% w/v = g of solute/ mL of solution × 100

A 1% w/v means that you have 1 g of PPP per 100 mL of solution

Thus, if you need to make 500 mL of solution you will need 5 g of PPP.

I hope it helps!