S3 Chem Bk1 (U1-4)

A pure substance that is made up of two or more elements chemically combined together is called a ____.

Which of the following correctly describes a tin of soft drink?

• It is an element

• It is a compound

• It is a mixture

• It consists of oxygen

Which of the following is/are physical properties?

• Senses (e.g. odour, taste)

• States (e.g. gas, liquid, solid)

• Releases bubbles (e.g. releases $CO_2$ )

• Conductivity (i.e. will it conduct electricity)

Which of the following should be labelled on a jar containing oxygen?

• 
• 
• 
• 

What should be used to transfer a few mL of hydrochloric acid(aq)?

____ can seperate oxygen, argon and nitrogen from the atmosphere.

Suggest why helium is used to fill airships?

• Helium has a density lower than air

• Helium has an octect structure

• Helium is unreactive

• Hydrogen is explosive

A hot saturated sodium chloride solution is left in room temperature for a day. Suggest what process it will undergo and the results.

• Sedimentation, sodium chloride sediments to the bottom

• No process, the solution remains unchanged

• Evaporation, only sodium chloride is left

• Crystallization, sodium chloride forms crystals

We can use ____ to obtain clean water from sea water.

What should be used to clean the platinum wire before carrying out a flame test?

• Dilute hydrochloric acid

• Tap water

• Concentrated hydrochloric acid

• Distilled water