Selina Elements, compunds and acids

What does the flammable hazard symbol indicate?

• The substance can catch fire easily.

• The substance is toxic.

• The substance is corrosive.

• The substance is an irritant.

What does the health hazard (harmful) symbol indicate?

• The substance is dangerous to everything.

• The substance can catch fire easily.

• The substance may explode.

• The substance is an irritant.

Which of the following descriptions matches the corrosive hazard symbol?

• This may dissolve or burn materials, including skin.

• This can catch fire easily.

• This may explode.

• This includes irritants, harmful substances, and some low-hazard substances.

What type of acids are used in science lessons and have fewer acid particles than a concentrated acid solution?

• Concentrated acids

• Weak acids

• Dilute acids

• Strong acids

Which acid can also be used in making food for plants and in paints?

• Sulfuric acid

• Nitric acid

• Ethanoic acid

• Tannic acid

An element is a pure substance that cannot be broken down into any other substances. An element is made from just one type of:

• molecule

• compound

• atom

• mixture

How many chemical elements are listed on the periodic table?

• 108

• 118

• 128

• 138

What is the chemical symbol for helium?

• H

• He

• Hi

• Hm

Which of the following is true about element symbols?

• They always start with a lowercase letter.

• They can contain numbers.

• They always start with a capital letter.

• They are always three letters long.

Suggest why the symbol for silicon is Si and not S.

• Because S is already used for sulfur

• Because Si is the first two letters of silicon

• Because S is not a valid symbol

• Because Si is easier to remember