You dissolve 25 g of CaSO4 in water and dilute to 1500 mL. What is the molarity of this solution?
moles CaSO4 = grams/molar mass = ?
Then M = moles CaSO4/1.5 L = ?
25g / 136.4 = 0.087
0.087/ 1.5L
= 0.085?
I have no idea what you're doing wrong but the first division is not correct and neither is the second one. If you're doing this with a calculator are you using the calculator correctly? It might be a good idea to divide something you know the answer; i.e.,
10/5 = 2.0
125/13 = 9.615
100/25 = 4.0
yeah it was my calculator, i figured it out though. however, when you respond to questions you could be a little nicer. thanks for the help :)
To find the molarity of a solution, you need to know the amount of solute (in moles) and the volume of the solution (in liters).
First, you need to convert the given mass of CaSO4 (calcium sulfate) to moles. The molar mass of CaSO4 is calculated as follows:
Ca = 40.08 g/mol
S = 32.06 g/mol
O4 = (16.00 g/mol) x 4 = 64.00 g/mol
Molar mass of CaSO4 = 40.08 g/mol + 32.06 g/mol + 64.00 g/mol = 136.14 g/mol
Now, you can calculate the number of moles of CaSO4 in 25 g using the formula:
n = m/M
where n is the number of moles, m is the mass in grams, and M is the molar mass.
n = 25 g / 136.14 g/mol ≈ 0.1835 mol
Next, you need to convert the given volume of the solution from milliliters to liters:
1500 mL = 1500 mL / 1000 mL/L = 1.5 L
Finally, you can calculate the molarity (M) using the formula:
M = n/V
where M is the molarity, n is the number of moles, and V is the volume in liters.
M = 0.1835 mol / 1.5 L ≈ 0.1223 mol/L
Therefore, the molarity (concentration) of the CaSO4 solution is approximately 0.1223 mol/L.