February 2025

Natural Ecosystems

By |2025-02-12T09:01:20+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Impala ecosystem Natural ecosystem. Image credit wordpress.com ZIMSEC O Level Combined Science Notes: Natural Ecosystems

  • In a natural ecosystem there is close interaction between the plants and animals
  • The green plants are the producers
  • The animals are the consumers
  • There are several levels of consumers
  • Primary consumers-these eat plants directly
  • They are also known as herbivores
  • Secondary […]
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Sole Trader: Simple Statement of Financial Position Example 1

By |2025-02-12T09:35:06+02:00February 12th, 2025|Notes, Ordinary Level Notes, Principles of Accounts Notes|

ZIMSEC O Level Principles of Accounts Notes: Sole Trader: Simple Balance Sheet Example 1

  • From the following trial balance of S Madondo, extracted after one year’s trading, prepare a trading and profit and loss account for the year ended 31 December 20X6 and  a balance sheet as at 31 December 20×6

Inventory at 31 December 20X6 was $12,408

Solution

  • The […]
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Experiment:Hydrogen as a reducing agent

By |2025-02-12T09:45:03+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment:Hydrogen as a reducing agent

Aim: To show that hydrogen can act as a reducing agent

Materials: hard glass test-tube with a small hole near the end, copper oxide, burner, cork with a short glass tube, rubber tube

Reducing copper using hydrogen Reducing copper using hydrogen

Method

  1. Place a spatula load […]
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Experiment: Demonstrate the effect of surface area on the rate of a reaction

By |2025-02-12T09:14:05+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

 ZIMSEC O Level Combined Science Notes: Experiment: Demonstrate the effect of surface area on the rate of a reaction

Materials: magnesium ribbon, magnesium powder, marble chips (another form of calcium carbonate), powdered calcium carbonate, 250cm3 beakers, dilute hydrochloric acid, spatula, splint

Method a

  1. Into two beakers pour an equal volume of dilute hydrochloric acid about 20cm3
  2. Add a small spatula load […]
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Extraction of copper from oxides

By |2025-02-12T09:29:40+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Extraction of copper from oxides

  • In addition to sulphides
  • Copper ore can also be in the form of oxides
  • For example Cuprite
  • Unlike withe sulphides the oxygen in copper oxides cannot be driven off by roasting
  • Copper can be yielded by using the reduction process
  • Sodium carbonate is used in the process
  • It […]
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Uses of sulphuric acid

By |2025-02-12T09:43:37+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Uses of sulphuric acid

  • Most of the sulphuric acid produced at Zimphos is used to
  • make fertilizers (mostly superphoshate)
  •  Some of the sulphiric acid is used to  manufacture aluminum sulphate
  • Which in turn is used as a flocculent in water purification processes
  • Bauxite from Mutare is dissolved into sulphuric acid
  • The word […]
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Experiment: Demonstrating that carbon dioxide extinguishes a burning flame

By |2025-02-12T09:10:46+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Carbon dioxide extinguishes flames Carbon dioxide extinguishes flames ZIMSEC O Level Combined Science Notes: Experiment: Demonstrating that carbon dioxide extinguishes a burning flame

Aim: to show that carbon dioxide extinguishes a flame

Materials:  3 different sized candles, vinegar, baking soda, beaker or plastic bottle, shallow dish

Method

  1. Place the 3 pieces of candle in a […]
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