Chemical reaction in aqueous solutions

Question 1

What are the unusal properties of water? (5)

Answer 1

1. Very high melting and boiling points, due to extensive hydrogen boning.
2. Water becomes more dense when it melts. Creating ice to float and lake to freeze from the top downwards.
3. The freezing point of water decreases as pressure increases
4. Water has relatively large surface tension and heat capacity.
5. High in concentration

Question 2

Why is Ice less dense than liquid water?

Answer 2

Liquid water, the molecules move around close to each other, continuously making and breaking hydrogen bonds with their neighbours. In solid water molecules are rigidly heild in a structure which maximised the possible number of hydrogen bonds.

Question 3

Why do non-polar molecules still dissolve in water?

Answer 3

Because the permanent dipole of water can induce a dipole in the non-polar molecule. Creating an instantaneous dipole in the non-polar molecule.

Question 4

What does instantaneous dipole mean?

Answer 4

Separation of charges in a non-polar molecule at an instant due to a sudden disturbance in the electric cloud around the molecule.

Question 5

What is an electrolyte and a non-electrolyte?

Answer 5

Dissolves to give ions

Dissolves without the formation of ions

Question 6

What is a strong electrolyte?

Answer 6

Fully dissociates forms into ions.

Uses straight arrow

Question 7

What is a weak electrolyte?

Answer 7

Incomplete dissociation with water. Most form molecules but some form ions. Mainly weak acids. use equilibrium arrow.