The Answer is C
<span> It can be separated by physical means and is uniform in composition.</span>
I believe that A is the answer. :)
The reaction equation:
N₂O₅ + H₂O → 2HNO₃
Moles N₂O₅ = 0.65 / (14 x 2 + 16 x 5)
Moles N₂O₅ = 6.02 x 10⁻³
Molar ratio N₂O₅ : HNO₃ = 1 : 2
Moles HNO₃ = 2 x 6.02 x 10⁻³
Moles HNO₃ = 0.012 mole
Answer:

Explanation:
Titration is a method used to determine the concentration of a substance. The formula for this is:

Where M is the molarity of the acid or base and V is the volume of the acid or base.
We know that 46.0 milliliters of a 0.15 molar solution of nitric acid wereused in the titration. 25.0 milliliters of solution of calcium hydroxide of unknown molarity were also used.

Substitute these known values into the formula.

We are solving for the molarity of the base, so we must isolate the variable
. It is being multiplied by 25.0 milliliters. The inverse operation of multiplication is division, so we divide both sides of the equation by 25.0 mL.


The units of milliliters (mL) cancel.



The original measurements have 2 or 3 significant figures. We always round our answer to the least number of sig figs, which is 2. For the number we calculated, that is the hundredths place. The 6 in the thousandths place tells us to round the 7 up to an 8.

The concentration of calcium hydroxide is approximately <u>0.28 M.</u>