The unknown medium would be glass
Answer:
The weight/weight % or percent by mass of the solute is 1.04g.mL
Explanation:
We assume, (i) that the solvent is water, and (ii) that dissolution occurs without change in volume.
So given the standard density of water, the mass of the solution is simply,
(4.87+86.4)g
For solution, 
= 
= 1.04 g. mL
Because nitrate salts are soluble stuff, you could get significantly higher solution densities if you dissolved more salt (volume change would be fairly negligible).
Answer:
increasing the length of time the beam is fired at the crystal
Explanation:
Interference pattern does not depend on duration of the recording, though this might affect clarity of the image on the photographic film. Other things will change where the electrons end up. Speed of electrons affects its momentum, and thus its position. Proton has different mass, so different interference pattern. A different crystal will create a different interference pattern depending on the molecular formula.