February 2025

Poultry and Rabbit feeds

By |2025-02-12T09:29:54+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Poultry and Rabbit feeds

Chickens

  • Food forms the major part of costs when rearing poultry for eggs and meat.
  • It is therefore vital that the poultry  feed is obtained, mixed and given to chickens in the most economic and cost saving way.
  • The range of feed and the composition of the diet depends on […]
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Reproduction in plants: Comparing different plant seeds and fruits

By |2025-02-12T09:31:29+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Different fruits showing their seeds. Image credit blogspot.com Different fruits showing their seeds. Image credit blogspot.com ZIMSEC O Level Combined Science Notes: Reproduction in plants: Reproduction in Plants:Comparing different fruits and seeds  

Materials: a variety of fruits

Method

  1. Collect and gather different types of fruits that are found in your area
  2. Group the fruits […]
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Experiment: Finding soil organisms

By |2025-02-12T08:56:32+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Finding soil organisms. Finding soil organisms. ZIMSEC O Level Combined Science Notes: Experiment: Finding soil organisms

Materials: digging tools, pen and paper, tweezers, gauze, beaker, filter tunnel, light bulb, clamp stand, microscope/hand lens, containers

Method

  • Go out and look for soil organisms. Look for things such as holes in the soil
  • Take soil samples
  • Set up […]
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Oxidation of iron/Rusting

By |2025-02-12T09:44:16+02:00February 12th, 2025|Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Oxidation of iron/Rusting

  • Iron combines with oxygen to form rust
  • The oxidation process of iron is known as rusting
  • Rust is a reddish-brown crust that forms on iron
  • It is iron oxide
  • \text{iron+oxygen}\rightarrow\text{iron oxide}
  • Most iron objects such as nails, paper clips, wires and iron coins rust when they are exposed to the […]
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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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