Grade 8 Science Mid-Term Review

  There are how many atoms found and created in the universe right now?

• 94

• 24

• 118

• 134

What is the meaning of atom?

• It is the last part of the molecules that cannot be divided.

• The part of moleclues which can be multiplied.

• The negatively charged particles of molecules.

• none of the above.

The molecules of oxygen has how many oxygen atoms?

• three

• five

• hundreds

• two

How many kinds of atoms compose an element?

• two

• one

• three

• many

What is the symbol for potassium?

• K

• P

• Po

• Hg

What is the symbol for gold?

• Ag

• Au

• G

• Go

Mixtures contain different elements and/or compounds that are joined together chemically (bonded).

• true

• false

Black ink looks as if it is just one colour. In fact, it is a mixture of different colours. You can separate out the different colours using a technique called _________________.

• chrome

• geography

• chromatography

• photography

A red powder was placed into a beaker of water. After it was stirred the water looked cloudy and lumps of powder could still be seen. Has a solution been formed?

• Yes, because it was stirred.

• No, because a solution should be applied with fire.

• Yes, because it looked cloudy.

• No, because a solution should have one color and lumps should disappear.

A solution is made when a solute is dissolved in a solvent. Which of the following sentences is true about solutions?

• A diluted solution has more particles of the solute dissolved in it than a concentrated solution.

• A saturated solution can accommodate more solute.

• A concentrated solution has more particles of the solute than in diluted solution.

• A concentrated solution has more particles of the solvent.