I have a pre lab questions that are due in a few hours and I need help. Theres several questions

In the titration of 25.00 ml of a water sample, it took 20.590 ml of 4.995x10-3 M EDTA solution to reach the endpoint.

The total hardness is due to one or a combination of Ca2+, Mg2+, and Fe2+ in your sample. It is convenient to express this hardness as though it was entirely due to Ca2+. Making this assumption, determine the number of moles of Ca2+ present in the bottled water sample titrated.
The total hardness is always listed in parts-per-million (ppm) of CaCO3 (or mg CaCO3 / Kg H2O). Since the density of water is 1.0 g/ml, one ppm would be the same as the number of mg of CaCO3 per liter of water. Determine the number of moles of CaCO3 present in the titrated sample of water, assuming that all the Ca2+ combines with CO32−.

Calculate the number of grams of CaCO3 present and convert to mg.

Convert the number of ml of bottled water used in eache sample titration to Liters.

Calculate the ppm of CaCO3 = mg CaCO3 / Liters H2O used.

Oh, water chemistry, how refreshing! Let's dive in and tackle these questions one by one, shall we?

First, we need to determine the moles of Ca2+ in the water sample. Since we assume all the hardness is due to Ca2+, we can use the titration result.

But before we begin, may I ask, did the water sample titration ask for its opinion on life? Because it would say, "Water you waiting for? Let's find the answer!"

Alright, jokes aside, to find the moles of Ca2+, we'll use the balanced equation. With each molecule of EDTA reacting with one Ca2+ ion, we have a 1:1 mole ratio.

So, Moles of Ca2+ = Moles of EDTA used in titration.
= Concentration of EDTA solution (M) × Volume of EDTA solution (L)

Now comes the exciting part, expressing the total hardness as CaCO3. According to Avogadro, there's a whole mole of CaCO3 for each mole of Ca2+. So Moles of CaCO3 = Moles of Ca2+.

Next, since we are so curious about weights, let's find the weight of CaCO3 in grams. We'll use its molar mass (apologies for using big words: 1 Ca + 1 C + 3 O = 100.09 g/mol) multiplied by Moles of CaCO3.

To convert grams to milligrams, we'll perform an epic transformation. 1 g = 1000 mg. Voila!

Now, let's make some big to small conversions, like shrinking sweaters in the wash! Convert milliliters to liters by dividing by 1000. Remember, mL is just the fancy way of saying cubic centimeters (cm³).

Lastly, let's calculate the ppm of CaCO3. PPM stands for "Pretty Perfect Mathematics" (just kidding), it stands for "parts per million."

PPM of CaCO3 = (mg CaCO3 / Liters of H2O used)
= mg CaCO3 / 1000

And there you have it! You've escaped the complexity circus and arrived at the answers. Good luck with your pre-lab questions, my friend, and remember, laughter is the best scientific reaction!

Sure! Let's break down each question and solve them step by step:

1. Determine the number of moles of Ca2+ present in the bottled water sample titrated:
- We know that 20.590 ml of 4.995x10-3 M EDTA solution was used in the titration.
- The molarity (M) of the EDTA solution is given as 4.995x10-3 moles/liter (mol/L).
- Convert ml to liters by dividing by 1000: 20.590 ml = 20.590/1000 = 0.02059 liters.
- Now, we can calculate the number of moles of Ca2+ by using the formula:
Moles of Ca2+ = Volume of EDTA solution (liters) x Molarity of EDTA solution
Moles of Ca2+ = 0.02059 L x 4.995x10-3 mol/L

2. Determine the number of moles of CaCO3 present in the titrated sample of water:
- Assuming that all the Ca2+ combines with CO32−, the ratio of moles of CaCO3 to Ca2+ is 1:1.
- Therefore, the number of moles of CaCO3 is the same as the number of moles of Ca2+.

3. Calculate the number of grams of CaCO3 present and convert to mg:
- To find the number of grams of CaCO3, we need to use the molar mass of CaCO3.
- The molar mass of CaCO3 is 40.08 g/mol.
- Multiply the number of moles of CaCO3 by its molar mass to get the number of grams:
Grams of CaCO3 = Moles of CaCO3 x Molar mass of CaCO3
Grams of CaCO3 = Moles of CaCO3 x 40.08 g/mol
- To convert grams to milligrams, multiply the result by 1000:
Milligrams of CaCO3 = Grams of CaCO3 x 1000

4. Convert the number of ml of bottled water used in each sample titration to Liters:
- Divide the volume in milliliters by 1000 to get the volume in liters.

5. Calculate the ppm of CaCO3:
- The ppm (parts per million) of CaCO3 is calculated as the number of mg of CaCO3 per liter of water used.
- Divide the number of milligrams of CaCO3 by the number of liters of water used to get the ppm:
ppm of CaCO3 = Milligrams of CaCO3 / Liters of H2O used.

I hope this helps! Let me know if you have any further questions.

To answer these pre-lab questions, let's break them down one by one:

1. Determining the number of moles of Ca2+ present in the bottled water sample titrated:

Given:
- Volume of EDTA solution used (V1) = 20.590 ml
- Concentration of EDTA solution (C1) = 4.995x10-3 M

The balanced chemical equation for the reaction between EDTA and Ca2+ is:
Ca2+ + EDTA → Ca-EDTA

From the balanced equation, we can see that the mole ratio between Ca2+ and EDTA is 1:1. This means that the number of moles of Ca2+ is equal to the number of moles of EDTA used.

To find the number of moles of Ca2+, we can use the equation:
moles of Ca2+ = concentration of EDTA solution (C1) * volume of EDTA solution used (V1) / 1000

Substituting the given values:
moles of Ca2+ = (4.995x10-3 M) * (20.590 ml) / 1000 = X moles (calculate the final value)

2. Determining the number of moles of CaCO3 present in the titrated sample of water:

Since we are assuming that all the Ca2+ combines with CO32-, the mole ratio between Ca2+ and CaCO3 is 1:1. Therefore, the number of moles of CaCO3 is also equal to the number of moles of Ca2+.

So, the number of moles of CaCO3 is equal to the X moles calculated in the previous step.

3. Calculating the number of grams of CaCO3 present and converting to mg:

The molar mass of CaCO3 is:
Ca = 40.08 g/mol
C = 12.01 g/mol
O = 16.00 g/mol

Molar mass of CaCO3 = (40.08 + (12.01 * 1) + (16.00 * 3)) g/mol = Y g/mol (calculate the final value)

To find the number of grams of CaCO3, we can use the equation:
grams of CaCO3 = number of moles of CaCO3 * molar mass of CaCO3

Substituting the values:
grams of CaCO3 = (X moles) * (Y g/mol) = Z g (calculate the final value)

To convert grams to milligrams, we can use the equation:
milligrams of CaCO3 = grams of CaCO3 * 1000

Substituting the value:
milligrams of CaCO3 = (Z g) * 1000 = W mg (calculate the final value)

4. Converting the number of ml of bottled water used in each sample titration to liters:

To convert milliliters (ml) to liters (L), we need to divide the volume in milliliters by 1000.

So, the volume in liters is:
volume in liters = volume in milliliters / 1000

Substituting the value:
volume in liters = (given value of ml) / 1000 = A L (calculate the final value)

5. Calculating the ppm of CaCO3 = mg CaCO3 / Liters H2O used:

The given formula for ppm of CaCO3 is:
ppm of CaCO3 = milligrams of CaCO3 / liters of water used

Substituting the values:
ppm of CaCO3 = (W mg) / (A L) = B ppm (calculate the final value)

So, by following these steps and substituting the given values, you can get the answer to each of the pre-lab questions.

mols EDTA = M x L = ?

mols Ca^2+ = same as mols EDTA

g CaCO3 = mols x molar mass CaCO3. That's g CaCO3 in 25.00 mL.
Convert that to mg/L for ppm CaCO3.