February 2025

Advantages and disadvantages of vegetative production

By |2025-02-12T09:36:14+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Sugarcane field. Image credit gov.ph Sugarcane field. Image credit gov.ph ZIMSEC O Level Combined Science Notes: Reproduction in plants: Advantages and disadvantages of vegetative (asexual) production  

  • A lot of plants which grow using the vegetative method of reproduction are able to produce seeds
  • They use vegetative reproduction because it has certain advantages

Advantages

  • New […]
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Selection

By |2025-02-12T08:59:43+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Selection

  • Each time male and female individuals reproduce they create an offspring that is different from themselves
  • This changes accrue over time to bring about much change in the descendants as there is inter-breeding between many individuals in each generation
  • This changes might result in the offspring having certain advantageous characteristics that are […]
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Experiment: to show changes in shape and volume of iodine crystals when they are heated

By |2025-02-12T09:11:39+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

sublimation_of_iodine-min

ZIMSEC O Level Combined Science Notes: An  experiment To show changes in shape and volume of iodine crystals when they are heated

Materials: evaporation dish/tin lid, glass filter funnel, burner, burner stand, one iodine crystal

Method

  1. Place the iodine crystal into an evaporation dish
  2. Put the filter funnel upside down over the crystal
  3. Warm the crystals […]
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Cash Discount,Discount Received and Discount Allowed

By |2025-02-12T09:05:08+02:00February 12th, 2025|Notes, Ordinary Level Notes, Principles of Accounts Notes|

Cash Discount. Image credit wiser.com Cash Discount. Image credit wiser.com ZIMSEC O Level Principles of Accounts Notes: The Cash Book:Discount Received and Discount Allowed

  • Businesses prefer it if their customers pay quickly
  • Businesses may thus accept a sum slightly lower than the invoice amount in settlement of a debt if payment is […]
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Experiment: Testing the physical properties of metals and non-metals

By |2025-02-12T09:23:02+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Common non-metals. Image credit blogspot.com Common non-metals. Image credit blogspot.com ZIMSEC O Level Combined Science Notes: Experiment: Testing the physical properties of metals and non-metals

Aim:To examine the physical properties of metals and non-metals

Materials: aluminium foil, carbon rod taken from a torch cell, copper foil, gas jars of oxygen, hydrogen; sulpher, […]

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The oxidation process

By |2025-02-12T09:42:38+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: The oxidation process

  • Oxygen can be added to a substance/compound/element
  • For example carbon may be burnt into the air to form carbon dioxide
  • This process is known as oxidation
  • Oxidation is the process by which a substance/compound/element combines with oxygen in a chemical reaction
  • Oxidation is also used to refer to a […]
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Experiment: Investigating the neutralisation process

By |2025-02-12T09:10:28+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment: Investigating the neutralisation process

Aim: To find out what happens to the pH of an acid when a base is added

Materials: vinegar, plastic beaker, measuring cylinder, stirring rod, spatula/plastic teaspoon, slaked lime (calcium hydroxide), universal indicator paper

Method

  1. Place about 10 cm3 of vinegar in a beaker
  2. Dilute it with an equal volume of water
  3. Remove […]
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Purification of copper using electrolysis

By |2025-02-12T09:27:29+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Electrolysis of copper. Image credit 180daysofteaching.wordpress.com Electrolysis of copper. Image credit 180daysofteaching.wordpress.com ZIMSEC O Level Combined Science Notes:Purification of copper using electrolysis

  • The impure copper (blister copper) yielded from the converter
  • Is then molded into thick sheets
  • These sheets become positive plates i.e.
  • they are connected on the positive side […]
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