O Level Science Notes Archives - Page 26 of 33 - Free ZIMSEC & Cambridge Revision Notes

Inhaled vs Exhaled air experiment: Method 2

By garikaib|2025-02-12T09:40:39+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Lime water is used to test for carbon dioxide. Image weebly.com ZIMSEC O Level Combined Science Notes: Inhaled vs Exhaled air experiment: Method 1

Aim: Test to compare the composition of exhaled and inhaled air.

Materials: Limewater (to test for the presence […]

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Food types and their importance

By garikaib|2025-02-12T09:11:37+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Different types of food have different functions. Image credit healthydietadvisior.com ZIMSEC O Level Combined Science Notes: Food types and their importance

Carbohydrates-these are energy-rich foods that are largely made up of starch and sugars. They are easily broken down in the […]

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Experiment: Growing plants using the vegetative reproduction method

By garikaib|2025-02-12T09:37:05+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Growing mulberry cuttings. Image credit wordpress.com ZIMSEC O Level Combined Science Notes: Reproduction in plants: Growing plants using the vegetative reproduction method

Materials; trays of soil/sand or prepared garden beds, plant cuttings of sugar cane, mulberry, sweet potato cuttings etc

Method Plant [...]
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Breeding

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

SeedCo trial fields are used for breeding seeds. Image credit seedco.co ZIMSEC O Level Combined Science Notes: Breeding

Controlled breeding in livestock and crops allow farmers to obtain animals and crops with the best characteristics
Each breed or variety has is […]

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Experiment: The heating curve of water

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

The heating curve of water. Image credit wordpress.com ZIMSEC O Level Combined Science Notes: Experiment: The heating curve of water

Materials: beaker, crushed ice, thermoter, burner, clock/watch with a stop watch function

Method

Half fill a beaker with crushed ice
Record the temperature of the ice
Place […]

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Properties of Nonmetals vs metals

By garikaib|2025-02-12T09:21:43+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Common metal objects. Image credit blogspot.com ZIMSEC O Level Combined Science Notes: Experiment: Properties of Metals and Non-Metals

Elements can be divided into two groups:
Metals and Non-metals
Examples of metals are: copper, zinc, iron, gold, silver, chrome, lead and tin
Almost all metals have certain properties that makes them […]

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Differences between reduction and oxidation
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Differences between reduction and oxidation

Notes, O Level Science Notes, Ordinary Level Notes

Differences between reduction and oxidation

By garikaib|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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Experiment: The effects of a catalyst on the rate of a reaction

By garikaib|2025-02-12T09:17:07+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Copper (II) can be used as a catalyst. Image credit chemistry-reference.com ZIMSEC O Level Combined Science Notes: Experiment: The effects of a catalyst on the rate of a reaction

Aim: To investigate the effects of a catalyst on a reaction using […]

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Galvinasing iron

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

Corrugated iron sheets are galvanised. Image credit alibaba.com ZIMSEC O Level Combined Science Notes: Galvinasing iron

Galvanising is one of the methods used to prevent iron from rusting
Iron and steel can be coated with zinc
Zinc is a fairly more reactive metal

[…]

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The production of Nitric acid
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The production of Nitric acid

Notes, O Level Science Notes, Ordinary Level Notes

The production of Nitric acid

By garikaib|2025-02-12T08:58:32+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: The production of Nitric acid

Some of the ammonia produced using the Haber process is used in the production of nitric acid
The first stage in the process of making nitric acid is the oxidation of ammonia
To form nitric acid
\text{ammonia + oxygen} \rightarrow\text{nitric oxide+ water+heat}
This an exothermic reaction

[…]

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February 2025