A hard water sample contains 0.0081 %Ca by mass (in the form of Ca2+ ions)What mass of water in grams contains 1.3g of Ca?

(1.3g of Ca is the recommended daily allowance of calcium for 19- to 24-year-olds.)

Need help set this up?

1.3 = .000081x

x = 16049.38

So, subtract the 1.3g from that

To find the mass of water that contains 1.3g of Ca, we can use the given percentage of Ca in the water sample.

First, we need to determine the mass of the water sample. Since the percentage of Ca in the water sample is given as 0.0081%, we can assume that the remaining mass (100 - 0.0081) % is water.

Let's set up the equation:

(0.0081/100) x Mass of water sample = Mass of Ca

Substituting the given values:

(0.0081/100) x Mass of water sample = 1.3g

Now, let's solve for the mass of the water sample:

Mass of water sample = (1.3g) / (0.0081/100)

Mass of water sample = (1.3g) / (0.000081)

Mass of water sample = 16,049.38 grams

Therefore, 16,049.38 grams of water contain 1.3g of Ca.

Sure! To find the mass of water that contains 1.3g of Ca, we first need to determine the amount of Ca2+ ions in the water sample. Then, we can use this information to establish a relationship between the mass of Ca and the mass of water.

Let's start by finding the amount of Ca2+ ions in the water sample. The concentration of Ca in the sample is given as 0.0081% (by mass) or 0.000081 in decimal form.

To determine the mass of Ca2+ ions, we need to find the weight percent of Ca in Ca2+ ions. Since calcium has an atomic mass of 40.08 g/mol and each Ca2+ ion has a mass of 2 x 40.08 g/mol, the weight percent of Ca in Ca2+ ions is:

(2 x 40.08 g/mol)/(2 x 40.08 g/mol + 16 g/mol) = 80.16%

Now, we can calculate the mass of Ca2+ ions present in the water sample by multiplying the total mass of the water sample by the weight percent of Ca in Ca2+ ions:

Mass of Ca2+ ions = 0.000081 x mass of water sample

Next, we can establish a relationship between the mass of Ca and the mass of Ca2+ ions. Since the molar mass of Ca2+ ions is 2 x 40.08 g/mol, the relationship between the mass of Ca and the mass of Ca2+ ions is:

Mass of Ca = (2 x mass of Ca2+ ions) / (2 x 40.08)

Now, we can solve for the mass of water that contains 1.3g of Ca:

Mass of water sample = Mass of Ca / 0.000081

Substituting the values we have:

Mass of water sample = (2 x 1.3 g) / (2 x 40.08 x 0.000081)

Calculating this expression will give us the mass of water in grams that contains 1.3g of Ca.