Using the rules for selecting symbols for the elements, which of the following could NOT be a correct symbol for a chemical element?
CA
Ch
A
Cc
Pure substances may be either __________ or compounds.
elements
mixtures
solutions
heterogeneous materials
___________ is NOT a pure substance.
Air
Sugar
CO2
Sulfur
Distillation is used to separate liquids with different:
boiling points
freezing points
solubilities
densities
The melting of candle wax is classified as a physical change because it:
produces no new substances
transfers energy
changes the chemical properties of wax
absorbs heat
Compounds can be broken down into their elements by:
chemical changes
distillation
physical changes
densities
Which of the following is an example of a chemical property?
reactivity
length
mass
color
Which of the following is an example of a physical change?
getting a haircut
cooking an egg
burning a candle
the formation of acid rain
Phase changes are examples of _____________ changes.
physical
chemical
heterogeneous
homogeneous
Which of the following is an example of an element?
oxygen
brass
rust
water
Which of the following is an example of a heterogeneous mixture?
pizza
brass
water
graphite
Density is defined as the mass per unit of:
volume
length
weight
width
Density is a ___________ property.
physical
chemical
homogeneous
heterogeneous
Which of the following is a compound?
salt
oxygen
brass
pizza
A ___________ contains two or more substances physically combined.
mixture
compound
homogeneous
chemical
A ___________ has elements combined in definite proportions.
compound
mixture
alloy
homogeneous
A solid solution of metals is called an __________.
alloy
compound
mixture
chemical
A compound can only be broken down using _________ changes.
chemical
physical
homogeneous
mixture
Mixtures that are uniformly mixed are called __________ or solutions.
homogeneous
heterogeneous
alloys
compounds
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