Answer: CoBr3 < K2SO4 < NH4 Cl
Justification:
1) The depression of the freezing point of a solution is a colligative property, which means that it depends on the number of particles of solute dissolved.
2) The formula for the depression of freezing point is:
ΔTf = i * Kf * m
Where i is the van't Hoof factor which accounts for the dissociation of the solute.
Kf is the freezing molal constant and only depends on the solvent
m is the molality (molal concentration).
3) Since, you are assuming equal concentrations and complete dissociation of the given solutes, the solute with more ions in the molecular formula will result in the solution with higher depression of the freezing point (lower freezing point).
4) These are the dissociations of the given solutes:
a) NH4 Cl (s) --> NH4(+)(aq) + Cl(-) (aq) => 1 mol --> 2 moles
b) Co Br3 (s) --> Co(3+) (aq) + 3Br(-)(aq) => 1 mol --> 4 moles
c) K2SO4 (s) --> 2K(+) (aq) + SO4 (2-) (aq) => 1 mol --> 3 moles
5) So, the rank of solutions by their freezing points is:
CoBr3 < K2SO4 < NH4 Cl
I think Bleach formula is <span>NaClO</span>
Explanation:
(1) The nucleus is positive and the electron cloud is positive.
(2) The nucleus is positive and the electron cloud is negative.
(3) The nucleus is negative and the electron cloud is positive.
(4) The nucleus is negative and the electron cloud is negative
Answer:
D. As white light passes through a prism , it bends and separates into different colors
Explanation:
When light enters a prism, it experiences a phenomenon called 'refraction'.
Refraction occurs when light crosses the interface between two mediums with different optical density; when this happens, the light bends and also changes speed.
The angle at which the ray of light is refracted into the second medium depends on the optical density of the two mediums, but also on the wavelength of the light.
In particular, longer wavelengths (red color) are refracted the least, while shorter wavelengths (violet color) are refracted the most.
As a result, when white light (consisting of all the colors of visible light) enters into a prism, they different wavelengths are separated: therefore, white light separates into different colors.
So, the correct answer is
D. As white light passes through a prism , it bends and separates into different colors
