Question

Calculate the mass of the solute 250 cm^3 of NH2SO4??​

Answer 1

Answer:

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Explanation:

If you know that the only thing dissolved is NaOH, (little “a”), then you could do a titration of a small amount of the solution with an indicator such phenolphthalein. See this: Other acids besides HCl may also work, but make sure that you know the concentration of the acid.

Here’s how to do that:

If you titrate, say 10 ml of the NaOH solution, from the concentration of the acid (call this Y) and the number of milliliters (ml), you’ll be able to figure the amount of OH- in the solution.

X moles OH- = (1 mole OH- / 1 mole HCl) * (ml of HCl) * (1.0 liters / 1000 ml) * (Y moles HCl / liter)

Note that the units all cancel nicely to give moles of OH-. With this, then you have

Z = concentration of OH- = (X moles OH- / 10 ml) * (1000 ml / liter)

Then you can calculate the amount of the NaOH in the 250 ml from the moles of NaOH in one liter:

Answer: moles NaOH in 250 ml = 250 ml * (1 liter / 1000 ml) * (Z moles NaOH / liter)

Answer 2

Answer:

2)

N = 1

N = M * x ( where is x valancy factor)

1 = M * 2 ( as 2 H ions are present in h2so4)

M = 1/2

M =  no. of moles / vol. of the solution

1/2 =  given mass / molecular mass * vol. of solution

1/2 = given mass*1000/ 98 * 250      ( mol. mass of h2so4 = 98)

given mass =  98 / 2*4 = 12.25 g