February 2025

The mammal heart

By |2025-02-12T09:20:21+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The structure of the human heart. The structure of the human heart. ZIMSEC O Level Combined Science Notes: The mammal heart

  • Is made up of muscle which contracts continuously throughout the mammal’s life.
  • The number of contractions differ from mammal to mammal
  • In elephants it contracts about 25 times/minute
  • In humans it contracts about 70-80 […]
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Ecosystems: The soil

By |2025-02-12T09:39:32+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Soil profile. Image credit nesoil.com Soil profile. Image credit nesoil.com ZIMSEC O Level Combined Science Notes: Ecosystems: The soil  

  • Soil is an important part of the ecosystem
  • It is a critical component of life on earth and agriculture
  • Soil thickness varies from a few millimeters to a several meters in places
  • Animals and plants […]
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Experiment: to show the cooling effect of methylated spirits

By |2025-02-12T09:13:32+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A bottle of methylated spirit. Image credit wilko.com A bottle of methylated spirit. Image credit wilko.com ZIMSEC O Level Combined Science Notes: Experiment: to show the cooling effect of methylated spirits

Material: cotton wool,methylated spirits

Method

  1. Dip a small piece of cotton wool into the methylated spirits
  2. Rub some of […]
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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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