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
A measured value is expressed as a number along with a corresponding unit. The unit represents the dimension of the measured value.
For example:
- Length of an object can be expressed as, value + dimension. for example 10 m where 'm' is the dimension of length; meters
- Volume can be expressed as, value + dimension, for example, 10 L where L is the dimension of volume; Liters.
Ans C) Dimension
Answer:
A
Explanation:
this is because the electrons are attracted to the protons, the stronger the attraction and energy level the closer the electrons are to the nucleus. this moves them to a higher energy orbital. For example in a Bohr diagram.
Answer:
2.At a given temperature, the KE of all gases is the same.KE depends only on Kelvin temperature
Explanation:
The kinetic molecular theory of gases provides a succint expalantion and insight into the behaviour of gases. The assumptions of the theory are stated below:
- Gases are made up of large number of identical molecules which are moving at different speeds.
- Spaces occupied by molecules of gases are negligible compared to the volume of the container.
- Molecules of gases are independent of one another.
- The molecules collide with themselves and the walls of the container elastically.
- The temperature of a gas is a measure of only the average kinetic energy of the molecules.
