February 2025

Common metals and their uses

By |2025-02-12T09:24:03+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Copper wires. Image credit globalminingobserver.com Copper wires. Image credit globalminingobserver.com ZIMSEC O Level Combined Science Notes: Common metals and their uses

  • Common metals include:
  • aluminium
  • iron and
  • copper

Copper

  • is a soft, malleable and ductile metal with very high heat and electrical conductivity
  • has a reddish-orange color
  • It is used in thermostat, in electrical wiring
  • It is also […]
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Differences between reduction and oxidation

By |2025-02-12T08:57:47+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Differences between reduction and oxidation

  • There are differences between oxidation and reduction
  • The table below shows the differences between oxidation and reduction:
  • Often reduction and oxidation occur in conjunction
  • That is at the same time and during the same reaction
  • For example:
  • \text{ammonia+oxygen}\rightarrow\text{water+nitrogen dioxide}
  • Nitrogen gains oxygen and losses hydrogen […]
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Reversible reactions

By |2025-02-12T09:17:50+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Reversible reactions

  • In a reversible reaction there is a forward reaction
  • And a backward reaction
  • Both take place at the same time
  • As a result there is an equilibrium between the reagents and their products
  • That is at some point during the reaction process the amounts of both the reagents and their […]
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The electroplating process

By |2025-02-12T09:32:31+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Chome plated metal. Image credit MediaWiki Chome plated metal. Image credit MediaWiki ZIMSEC O Level Combined Science Notes: The electroplating process

  • Metals can be protected from corrosion by plating (covering) them with a less reactive metal
  • The metal which does not react with oxygen protects the more reactive metal underneath it

    • […]

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The manufacture of fertilizers

By |2025-02-12T08:59:33+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes:  The manufacture of fertilisers

  • Some of the nitric acid produced at Sable Chemicals is used to make ammonium nitrate fertilizer
  • It is used as an input (feedstock) for the fertilizer plant at both Sable and Zimphos
  • To maintain soil fertility nitrogen containing compounds are added to the soil
  • Some of these fertilizers are […]
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The carburetor

By |2025-02-12T09:14:26+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A carburettor is an important part of the Petrol engine. Image credit MediaWiki A carburettor is an important part of the Petrol engine. Image credit MediaWiki ZIMSEC O Level Combined Science Notes: The carburetor

  • A carburettor is an essential part of Petrol engines
  • A typical carburettor has the following parts:
  • An […]
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Electrical Power

By |2025-02-12T09:30:22+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Electrical Power

  • Electric power is the rate of doing work or the rate of of using energy
  • Electric power is the rate which an electrical device is converting electrical energy into heat or light or any other form of energy e.g kinetic energy in an electric motor
  • When current flows through a wire some of […]
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The Alternating Current generator

By |2025-02-12T09:46:08+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A simple AC generator. Image credit electronics-tutorials.ws A simple AC generator. Image credit electronics-tutorials.ws ZIMSEC O Level Combined Science Notes: The Alternating Power generator

  • In an Alternating Current (AC) generator the current changes direction as the coil turns
  • An AC generator is made up a rectangular coil that rotates between the […]
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To investigate whether the length of a beam affects its strength

By |2025-02-12T09:11:03+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Testing the length and strength of beams Testing the length and strength of beams ZIMSEC O Level Combined Science Notes: Experiment:To investigate whether the depth of a beam affects its strength

Aim: To show how the length of a beam affects its strength

Materials: drinking straws, clamps, weights

Method

  1. Clamp the ends of a straw […]
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Experiment To show the effect of sulphuric acid on some materials

By |2025-02-12T09:27:31+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The effects of acid rain. Image credit penguinsofchemistry.wordpress.com The effects of acid rain. Image credit penguinsofchemistry.wordpress.com ZIMSEC O Level Combined Science Notes: Experiment To show the effect of sulphuric acid on some materials

Aim: To show the effect of sulphuric acid on some materials

Materials: dilute sulphuric acid, wood, copper, plastic, iron, steel, aluminium, […]

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