Substrand: "7.6 Solutions, solvents and solutes" (16 periods)

This sub-strand deals with solutions and mixtures. When two or more pure substances mixed together it forms a mixture. Some pure solid substances (solids) dissolve in liquids (solvent) to form a solution. While some pure substance do not dissolve in liquids. Water is a universal solvent. Mixtures can be separated by physical and mechanical methods. Water as universal solvent is very important to our life. For example our body is made of about 90% water. And we need to drink clean water every day. Traditionally we have methods of water purification.

Learner's should:

Learner's should:

Learner's should:

7.6.1 know pure substance, solutions and mixture (k)

7.6.1.1 identify some examples of the three types of mixtures;

• i. solutions (salt and water),
• ii. suspensions (sand and water),
• iii.colloids (milk in water)

7.6.2 be able to make different solutions (s)

7.6.2.1 produce a solution by dissolving solute in a solvent.

• i. sugar (solute) in water (solvent)
• ii. salt (solute) in water (solvent)
• iii. klin powder(solute) in water (solvent)

7.6.3 be able to separate insoluble and soluble substances from mixtures (s)

7.6.3.1 select appropriate methods and separate substances from mixtures;

• i. insoluble substances: decanting, sieving. filtering, gravity separation, centrifugation, magnet use.
• ii. soluble substances; evaporation, distillation, chromatography, and centrifugation

7.6.4 know some hazardous solvents and solutions (k)

7.6.4.1 identify common solutions and solvents around you that are hazardous

7.6.5 appreciate the process of getting clean drinking water (a)

7.6.5.1 select sources of clean drinking water for human use

7.6.6 be able to show local purification method (s)

7.6.6.1 use local water purification methods. Settling and decanting

7.6.7 understand importance of sewage purification (u)

7.6.7.1 identify methods of sewage treatment and explain it’s important