Page 101 - Innovator's Science-8

not evenly mixed throughout the mixture. Can you identify a few more
examples of non-uniform mixtures around you?

On the other hand, some mixtures have components that cannot be seen
separately even with the help of a microscope. For example, sugar and
water particles cannot be seen separately in their mixture. Such types of

mixtures, where the components are evenly distributed and cannot be
Uniform mixture of distinguished, are uniform in nature. Can you list a few uniform mixtures?
sugar and water
Do you know that stainless steel is also a mixture? Stainless steel contains
iron, nickel, chromium, and a small
amount of carbon. They are mixed so
uniformly that the entire mixture

appears the same throughout and one
cannot see the individual substances.
Such mixtures are known as alloys .
Brass, a mixture of copper and zinc,

and bronze, a mixture of copper and
Science tin, are some other examples of alloys. Utensils made of stainless
Bytes
steel, brass, and bronze
IS AIR A MIXTURE?
Testimony
The idea that air is a Air is a uniform mixture made up mainly of nitrogen, oxygen, argon, carbon
mixture of gases was first
established by Autoine dioxide, and water vapour. Nitrogen makes up about 78% of air and does
Lavoisier and Joseph not support burning, while oxygen, which is about 21%, is essential for
Priestley in the late 18th
century. Their most living beings to breathe and helps in combustion. Air also contains
experiments showed that small amounts of argon, carbon dioxide, and water vapour. When warm air
air contains mainly touches a cooler surface, the water vapour in the air condenses into tiny
oxygen and nitrogen,
along with small amounts drops of liquid water. This is why you may see water droplets on cold
of gases. surfaces. The carbon dioxide we exhale is also present in the air, and

experiments have shown its presence through simple tests. Overall, air is a
mixture of different gases that supports life and various natural processes.

Let us confirm the presence of carbon dioxide in the air.

Activity-1 Aim: To observe the reac on of calcium oxide with water and to prepare lime water.
• Take a glass tumbler and fill it half with water.
Experiential Learning
• Add a small amount of calcium oxide (quick lime) slowly to it.
What do you observe?
• Calcium oxide reacts vigorously with water to form calcium hydroxide and
releases heat.

• S r con nuously to make a solu on of calcium hydroxide. This solu on is called
lime water.

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Science-8