Using Models
For some test questions, yo will be asked to decide what a visual model represents. Look at the model below. Notice that there are two types of particles shown and notice how the particles are distributed. Use what yo observe to decide which answer is the best choice.
What type of matter does the model represent?
a solution
a colloid
a suspension
an element
a homogeneous mixture
(Answer: C)
Choose the letter that best answers the question or completes the statement.
All pure substances
contain only one type of atom.
can be broken down into simpler substances.
cannot be broken down into simpler substances.
have a fixed composition.
have a variable composition.
Which property can be used to separate a mixture by distillation?
melting point
boiling point
density
viscosity
conductivity
During which of these events does a chemical change occur?
Ice cubes melt.
A pot of water boils.
A heated iron bar turns red.
A paper clip is bent.
A cake rises in the oven.
Yo can be certain that a change is a chemical change if
the change cannot be reversed.
new substances form.
bubbles are produced.
a precipitate forms.
there is a color change.
Use the drawings to answer Questions 5 and 6.
Which of the drawings could represent a homogeneous mixture?
drawing I
drawing II
drawing III
drawings I and III
drawings II and III
Which of the drawings could represent an element?
drawing I
drawing II
drawing III
drawings I and III
drawings II and III