February 2025

Amylase enzyme experiment

By |2025-02-12T09:21:08+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Image credit schule-bw.de Image credit schule-bw.de ZIMSEC O Level Combined Science Notes: Amylase enzyme experiment

Experiment

Materilas: 1% amylase enzyme/saliva, 2% startch solution, visking tubing, reagents to test for starch and sugar, beakers.

Method A: Visking Tubing.

  • NB. The Visking Tubing is used to function/work as a small small intestine.
  • Prepare two model intestines by […]
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Reproduction in plants: Flowers and Pollination

By |2025-02-12T09:24:25+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The basic structure of a flower The basic structure of a flower: showing the reproductive organs ZIMSEC O Level Combined Science Notes: Reproduction in plants: Flowers and Pollination

  • Most plants have female and male sex cells which join at fertilization to produce seeds
  • This is known as sexual reproduction
  • Flowers are the reproductive organs […]
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Strength to Mass ratio

By |2025-02-12T09:13:19+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The cross section of beams The cross section of beams ZIMSEC O Level Combined Science Notes: Strength to Mass ratio

  • Engineers do away with materials that are under little stress so as to be able to build efficient structures in terms of weight and cost
  • The material that lies close to the neutral […]
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The reaction of metals with dilute acids

By |2025-02-12T09:38:29+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment: The reaction of metals with dilute acids

  • Metals also react with dilute acids such as
  • Dilute hydrochloric acid
  • Hydrogen gas is released as a by product of the reaction
  • Metals such as calcium, magnesium and zinc that react with water react even more vigorously with dilute acids
  • Metals that react with […]
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Neutralisation/Salts

By |2025-02-12T09:10:01+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Neutralisation/Salts

  • The acidity and alkalinity of a solution can be represented on the pH scale
  • If the pH is low i.e less than 7 then the solution is acidic
  • If the pH is high i.e higher than 7 then the solution is alkaline
  • If a solution has a pH of 7 […]
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Extraction of copper from sulphides

By |2025-02-12T09:26:36+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

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

  • Copper is extracted from various types of ore including sulphide ores
  • For example copper ores found on the Great Dyke near Mhangura is of the sulphide type
  • Once the sulphide ore is extracted from the earth
  • It is crushed to form a very fine powder which is then further […]
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Liquification of air

By |2025-02-12T09:40:17+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Sable chemicals plant. Image credit zimeye.net Sable chemicals plant. Image credit zimeye.net ZIMSEC O Level Combined Science Notes: Liquification of air

  • In Zimbabwe the air liquification plant is at Sable Chemicals
  • Two main components of air are separated:
  • Nitrogen and Oxygen
  • These two gases are used in either liquid or gas form

    • […]

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