Water and Solution

• More than 70% of the Earth's surface is covered by water.
• Water is a poor heat and electricity conductor.
• Water is colorless, odorless, and tasteless.
• Capillary action, due to cohesive and adhesive forces, allows water to be drawn up from the roots to the leaves of plants.
• Water is a basic need of all life on Earth and no life can survive without it.
• Water has a density of 1 g/cm^3.
• Water has high surface tension, which allows insects like daddy longlegs to stay afloat on water.
• The boiling point of water is 100°C, the freezing point is 0°C, and the melting point is 0°C.
• Water is a compound made up of 2hydrogen and 1oxygen
• Adhesive force is a force that attracts different molecules
• Cohesive force is a force that attracts the same molecules.
• Electrolysis is used to determine the composition of elements in a water molecule.
• The ratio of the volume of gas produced is 1:2 (anode:oxygen gas, cathode:hydrogen gas).
• The chemical symbol of water is H2O.
• Electrolysis involves positive and negative electrodes (anode and cathode).
• Dilute hydrochloric acid is added to distilled water because water is a poor electricity conductor.
• During electrolysis, oxygen gas is produced at the anode and hydrogen gas is produced at the cathode.
• Oxygen gas can be tested by using a glowing wooden splinter, which reignites.
• Melting involves heat absorption. When heat is absorbed, the water particles will receive heat energy and move faster. Thus, convert the solid form to liquid.
• Impurities in water such as Salt:

  • decreases the melting point
  • increases the boiling point
  • changes the taste
  • causes water to become denser
• Hydrogen gas can be tested by using a glowing wooden splinter, which produces a “pop” sound
• Water is a universal solvent, meaning it can dissolve a wide variety of substances.
• Water is used as a solvent in the production of soft drinks.
• Organic solvents, which are carbon-based, can be used to dissolve solutes that are insoluble in water.
• Water is used as a solvent in domestic use and also as a raw material in the manufacturing industry, agriculture, and medicine.
• Water can be used for cooking, cleaning, bathing, and can dissolve different seasonings, detergents, and soaps.
• Water is used in agriculture as fertilizers dissolve in water and are absorbed by the roots of plants.
• Organic solvents are volatile and can be used in manufacturing aerosol substances such as spray paint, perfumes, and pesticides.
• Water is known as a universal solvent as it can dissolve almost all substances, solids, liquids, or gases.
• Examples of organic solvents include alcohol, kerosene, acetone, turpentine, and ether.
• Factors affecting the rate of solubility include the temperature of the solvent, rate of stirring, and size of the solute.
• High temperature and rate of stirring cause particles to move rapidly, filling up the spaces between solvent and solute faster.
• The higher the temperature of the solvent, the higher the rate of solubility.
• The smaller the size of the solute, the higher the rate of solubility.
• Solubility is the maximum amount of solute that can dissolve in 100 ml of solvent at a specific temperature.
• The higher the rate of stirring, the higher the rate of solubility.
• Smaller sized solutes means bigger total surface exposed to solvent particles.
• Cold temperature caused solute particles and solvent particles to move slowly. Therefore, solute and solvent particles slowly fill up the spaces between them.
• Water is a compound because it is produced when oxygen and hydrogen react chemically.
• Boiling point of water increases as salt is added.