Omitted options and they are
a) pure compound.
b. pure element.
c. pure substance.
d. homogeneous solution.
e. heterogeneous solution
Answer:d. homogeneous solution.
Explanation:
Pure substances or elements or compounds have a definite and sharp melting or boiling point, Any substance that is not pure is impure and will have different temperature of melting or boiling points.
To this effect, the clear colorless liquid cannot be a Pure substance, element or compound.
We can therefore say that the clear colorless liquid would be a homogeneous solution because a homogeneous solution is a mixture of constituents which completely mixes together such that each constituents cannot be seen with naked eye, When heated to boiling, each constituent in the mixture will give different boiling points.
A heterogeneous Solution, too is a mixture but contains constituents that can be seen and not a clear colourless solution.
Therefore On the basis of this information, we can say that the material in the beaker was a Homogeneous solution
Answer:
Sodium fluoride (NaF) does indeed follow the octet rule without any violations.
Answer:
Enthalpy change for the dissolution of the unknown solid = 4.6 Kj/mole
Explanation:
Using Q = m x Cs x ΔT ................................(1)
where Q = Amount of heat absorbed
m = Mass of solution
Cs = Specific heat capacity of solution
ΔT = Change in temperature
Given Density of solution = 1.20 g/ml
And volume of solution = 150 ml
Mass of solution = density x volume
= 1.2 x 150
= 180 g
From equation (1)
Q = 180 x 4.18 x 19.2 = 14446.08 = 14.4 Kj
So, ΔH of the dissolution of the unknown solid = 
= 
= 4.6 kj/mole
