Chemistry Solutions and Properties Quiz

Study Notes

Water molecules form hydrogen bonds, which create a more open structure in solid (ice) than liquid water.
This increased space between molecules results in the lower density of ice compared to liquid water.

Hydrogen bonds are formed between molecules due to the polar nature of water molecules.

Molarity is calculated by dividing the number of moles of solute by the volume of the solution in liters.
For example, 2.5 moles of calcium chloride dissolved in 5000 mL (5 L) solution.

Pure water dissolves salts because of its polar properties.
Salts consist of a positively charged ion (cation) and a negatively charged ion (anion).
Cations are attracted to anions.
As salinity increases, density increases.

Cohesion is the attraction between like molecules. Water molecules are attracted to each other by hydrogen bonds.
Adhesion is the attraction between unlike molecules. Water molecules are attracted to other surfaces such as the walls of a glass vessel.
These two properties help water to move upwards against the force. of gravity, which enables plants to transport water from their roots to their leaves.

The molecules in liquid water can move around more freely than the molecules in ice.
In ice, water molecules form a crystal lattice structure in which they are held apart by hydrogen bonds.
This ordered structure decreases the density of solid water, leading to the well-known phenomenon of ice floating.

Hydrogen bonds are weak bonds formed between a slightly positive hydrogen atom of one molecule and a slightly negative atom (such as oxygen or nitrogen) of another molecule.
The formation of hydrogen bonds in water contributes to its high melting point, boiling point, and surface tension.

The presence of salts in water lowers the freezing point of the water.
This is because salts form a strong attraction for water molecules, making it harder for water molecules to arrange themselves into the crystalline structure of ice.

Draw a diagram with a central oxygen atom (O) with two hydrogen atoms (H) bonded to it.
Each hydrogen atom has one electron shared with the oxygen atom, forming a shared electron pair, resulting in two individual covalent bonds between a hydrogen atom and the oxygen atom.
The oxygen atom has two lone pairs of electrons which are not involved in bonding. These lone pairs are not drawn on the diagram but are located on either side of the oxygen atom.
The molecule shape is bent, with hydrogen bonds present between molecules.
The bonding present is covalent bonding, where two atoms share one or more pairs of electrons.