Answer:- 14.9 M
Solution:- Given commercial sample of ammonia is 28% by mass. Let's say we have 100 grams of the sample. Then mass of ammonia would be 28 grams.
Density of the solution is given as 0.90 grams per mL.
From the mass and density we could calculate the volume of the solution as:

= 111 mL
Let's convert the volume from mL to L as molarity is moles of solute per liter of solution.
= 0.111 L
Now, we convert grams of ammonia to moles on dividing the grams by molar mass. Molar mass of ammonia is 17 gram per mole.

= 1.65 mole
To calculate the molarity we divide the moles of ammonia by the liters of solution:

= 14.9 M
So, the molarity of the given commercial sample of ammonia is 14.9 M.
Answer:
Colourless
Explanation:
We know that Y^3+ has the electronic configuration of;
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 (the 5s and 4d levels are empty).
According to the crystal field theory, the colour of complexes result from transitions between incompletely filled d orbitals.
As a result of this, complexes with empty or completely filled d orbitals are colourless. Thus, [Y(H2O)6]3 is colourless according to the Crystal Field Theory.
Answer: Mutations can cause instant adaptations, while natural selection is the process by which adaptations occurs over a series of generations. Adaptations are changes or processes of changes by which an organism or species becomes better suited for its environment. A mutation is an alteration of the DNA sequence.
D. Pentane. Pentane has 5 Carbon and 12 Hydrogen, like the molecule shown.
Answer:
1. B.10 mol/l
2. D.
3.A.
Explanation:
Totoo po yan ganyan po yong sakin