given a bottle containing 9M- H2SO4 calculate the number of
a) Grammes of the acud in 1 dm3
b) moles of the acid in 50 cm3
c) if 20cm3 of the acid were to be diluted to 1M, how many milliters of distilled water would be needed?
The mol wt of H2SO4 is 98 g/mole, so
(a) 9 moles, so ...
(b) 50mL * 1L/1000mL * 9moles/L = ___ moles
(c) 1/9 the concentration, so 9 times the volume, or 180cm^3.
So, you need to add 180-20 = ____ cm^3
Good
To answer these questions, we need to use the concept of molarity and the formula:
Molarity (M) = moles of solute / volume of solution in liters
Given that we have 9M H2SO4, we can proceed to solve each question:
a) Grams of the acid in 1 dm3:
To find the grams of acid in 1 dm3 (which is equivalent to 1 liter), we need to calculate the molar mass of H2SO4.
The molar mass of H2SO4 is:
2(1.008 g/mol) + 32.06 g/mol + 4(16.00 g/mol) = 98.09 g/mol
Now we can use the formula:
Molarity = moles of solute / volume of solution in liters
9M = moles of H2SO4 / 1 L
moles of H2SO4 = 9 mol/L * 1 L
moles of H2SO4 = 9 moles
To convert moles to grams, we use the molar mass:
Grams of H2SO4 = moles of H2SO4 * molar mass
Grams of H2SO4 = 9 moles * 98.09 g/mol
Grams of H2SO4 = 882.81 grams
Therefore, there are 882.81 grams of H2SO4 in 1 dm3.
b) Moles of the acid in 50 cm3:
We know the molarity of the acid is 9M. We can use the formula:
Molarity = moles of solute / volume of solution in liters
9M = moles of H2SO4 / 0.05 L (converted 50 cm3 to liters)
moles of H2SO4 = 9 mol/L * 0.05 L
moles of H2SO4 = 0.45 moles
Therefore, there are 0.45 moles of H2SO4 in 50 cm3.
c) Volume of distilled water needed to dilute 20cm3 of the acid to 1M:
To dilute a solution, we can use the concept of dilution. The formula for dilution is:
M1V1 = M2V2
Where M1 is the initial molarity, V1 is the initial volume, M2 is the final molarity, and V2 is the final volume.
Given that the initial molarity (M1) is 9M, the initial volume (V1) is 20 cm3, and the final molarity (M2) is 1M, we can rearrange the formula to solve for V2:
V2 = (M1 * V1) / M2
V2 = (9M * 20 cm3) / 1M
V2 = 180 cm3
Therefore, you would need 180 milliliters (ml) of distilled water to dilute 20 cm3 of the acid to 1M.