is neither combustible nor supporting of combustion (carbon dioxide is a good

example of this), then the flame will extinguish on the splint.

Wafting to smell a gas

Many gases have characteristic smells, so even if we don’t see the bubbling for

the formation of a gas, we can still detect its production via smell.

We never want to inhale a larger amount of a new compound produced in a

reaction. To avoid inhaling large amounts, we use a technique called “wafting.” To

waft you gently wave your hand over the top of a container and lift your hand to

your nose. This keeps the concentration that reaches your nose low to avoid

harmful impacts.

Observation 3: Formation of a Solid

Another common driving force for chemical reactions in solution is the formation

of a solid precipitate. We can detect the formation of a solid by seeing if a

solution gets cloudy (hard to see through) when we mix two liquids. A cloudy

solution means that solid particles are suspended in the liquid, signifying that a

solid was formed.

Clear, Cloudy, and Colorless

In the chemistry lab we use terminology that you use in your everyday life, but

sometimes it has a slightly different meaning in the chemistry lab.

In your everyday life you probably use clear and colorless as interchangeable

terms. But in chemistry they refer to two completely different ideas. In the

chemistry laboratory clear is the opposite of cloudy. When we say a solution is

clear, that means that there are not any suspended solids or gases in the

solution. Cloudy means there are suspended particles in the solution. A colorless

solution means that the solution has no color, and the opposite is when a solution

does have color.

In the chemistry lab we can have a clear red solution. Clear means it is free of

suspended particles and red gives the color. A clear and colorless solution both

has no particles and no color. We can also have a cloudy colorless solution or a

cloudy blue solution.

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