Thames & Kosmos Chemistry C500 (Version 2.0) handleiding

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Greenhouse Effect

Earth is surrounded by a protective envelope

known as the atmosphere, which holds in a

portion of the heat radiated by the sun. Just like

the panes of glass in a greenhouse, this

protective envelope is responsible for the

fact that our planet has a pleasant average

temperature of 15 °C. (Otherwise, it would

be bitterly cold: a mere –18 °C!)

The atmosphere is composed of gases, some of

which are responsible for the greenhouse effect

and are therefore known as greenhouse gases.

The best-known greenhouse gas is carbon

dioxide. All kinds of activities involving

combustion, such as driving a car or truck,

heating a house, or generating electricity at a

coal-ﬁred power plant, cause an extra portion of

carbon dioxide to get into our atmosphere. That

alters our protective envelope, which starts to

store too much heat. The temperature on Earth

increases, with consequences that we can’t even

predict today. Global warming is threatening to

bring about profound changes in our Earth’s

climate.

What’s clear is that we have to save energy. It's

better to get on a bike than drive a car. Don’t

turn the heat up too high and don't let

appliances keep running on standby power when

they’re not in use. That’s how we can preserve

our protective envelope.

Note:

Carbon dioxide gas is heavier

than air. Its ability to displace air

due to its greater weight can be

dangerous in cellars or caves.

There is no risk of suffocation

here, though.

Keyword:

Baking

Powder

A light and ﬂuffy cake is a

wonderful thing. But without a

certain ingredient, it won’t

turn out well. The magic

ingredient? Baking powder.

The most important

components of baking powder

are sodium bicarbonate

(“baking soda” in everyday

terms) and an acidiﬁer. What

happens in the batter is similar

to what you saw in the test

tube. The baking soda and the

acidiﬁer start to interact. What

comes out of it is carbon

dioxide gas, which bubbles

through the batter. The heat in

the oven intensiﬁes the

reaction even more. Lots of

little pores appear in the

batter to make it light and

ﬂuffy.

You can also see what’s

going on by adding a shot of

vinegar to some baking

powder — the mixture will

foam up dramatically. The

baking soda quickly reacts to

the acidic vinegar solution and

carbon dioxide is created.

14 | Effervescent Powder

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