Calculate the molarity of a phosphoric acid(H3PO3)solution that is 84% by mass phosphoric acid and has a density of 1.87g/mL.?
1.87 g/mL. mass of 1000 mL =
1.87g/mL x 1000 mL = 1870 grams.
How much of that is H3PO4? 84%, so
1870 x 0.84 = grams H3PO4 = 1571g
How many moles is that?
1571/molar mass H3PO4 about 16 moles.
16 moles/L soln = about 16 M.
I have rounded some of the numbers above; therefore, you need to go through and do it more accurately.
density H3PO4 = 1.689g/L
density = mass/volume
mass = 1.689 x 1000
= 1689g H3PO4 in 1000ml solution
1)85 wt%
1689g x 85/100 = 1435.65g H3PO4
(in 1000ml solution)
if you want to prepare 100ml of solution
1000ml = 1435.65g
100ml = A
A = 100/1000 x 1435.65g
= 143.57g H3PO4
*143.57g H3PO4 needed in prepare 100ml solution of 85wt%
2)37 wt%
1689g x 37/100 = 624.93g H3PO4
(in 1000ml solution)
if you want to prepare 100ml of solution
1000ml = 624.93g
100ml = A
A = 100/1000 x 624.93
= 62.49g H3PO4
*62.49g H3PO4 is needed in prepare 100ml solution of 37%
Well, let's break it down, shall we?
First, we need to find the moles of phosphoric acid in the solution. To do that, we'll use the mass percent and the density.
If the solution is 84% phosphoric acid by mass, then we can assume that 100g of the solution contains 84g of phosphoric acid.
Since density is mass per unit volume, we can calculate the volume of 100g of the solution. The density of the solution is given as 1.87g/mL, so 100g of the solution occupies a volume of 100g/1.87g/mL = 53.48 mL.
Now that we know the moles of phosphoric acid and the volume of the solution, we can calculate the molarity.
Molarity is defined as moles of solute per liter of solution. So, if we have 84g of phosphoric acid in 100g of solution, we can convert that to moles using the molar mass of phosphoric acid.
The molar mass of phosphoric acid (H3PO4) is approximately 98 g/mol.
Using the equation:
moles = mass/molar mass
moles of H3PO4 = 84g/98g/mol ≈ 0.857 moles
Finally, we can calculate the molarity using the equation:
molarity = moles/volume
molarity = 0.857 moles / 0.05348 L ≈ 16.04 M
So, the molarity of the phosphoric acid solution is approximately 16.04 M.
Now, excuse me while I go find some phosphoric acid to balance on my nose. It's always good to have a backup career as a chemistry clown.
To calculate the molarity of a phosphoric acid solution, we need to consider the mass of phosphoric acid and the volume of the solution.
First, let's determine the mass of the phosphoric acid in the solution. We know that the solution is 84% by mass phosphoric acid. So, if we have 100 grams of the solution, 84 grams of that will be phosphoric acid.
Next, we need to find the volume of the solution. We are given that the density of the solution is 1.87 g/mL. Density is defined as mass divided by volume, so we can rearrange the equation to solve for volume:
Volume = Mass / Density
Volume = 100 g / 1.87 g/mL
Volume ≈ 53.48 mL
Now that we have the mass of the phosphoric acid (84 g) and the volume of the solution (53.48 mL), we can calculate the molarity using the formula:
Molarity (M) = moles of solute / volume of solution (in liters)
We need to convert the mass of phosphoric acid to moles. The molar mass of H3PO4 is (1x3 + 16 + 1x4 = 97 g/mol).
Moles of solute = mass of solute / molar mass
Moles of solute = 84 g / 97 g/mol ≈ 0.866 moles
Finally, we need to convert the volume of solution from mL to L:
Volume of solution = 53.48 mL / 1000 mL/L ≈ 0.05348 L
Now, let's calculate the molarity:
Molarity = 0.866 moles / 0.05348 L ≈ 16.18 M
Therefore, the molarity of the phosphoric acid solution is approximately 16.18 M.