WorksheetsElements, Compounds, Mixtures Review
Total questions: 20
Worksheet time: 10mins
Which of these is most responsible for chemical reactions?
Electrons in the nucleus of the atoms
Electrons in the highest occupied energy level of the atoms
Electrons closest to the nucleus of the atoms
Electrons traveling the fastest toward the center of the atoms
CH4 + 2O2 → CO2 + 2H2O
In this reaction, the products are —
CH4 and 2O2
CH4 and CO2
2O2 and 2H2O
CO2 and 2H2O
CH4 + 2O2 → CO2 + 2H2O
In this reaction, the reactants are —
CH4 and 2O2
CH4 and CO2
2O2 and 2H2O
CO2 and 2H2O
In an experiment combining vinegar and baking soda, gas is given off. In this chemical reaction, the vinegar and baking soda are —
reactants
products
elements
suspensions
Which of the following molecules do not contain three atoms?
O3
N2
H2O
CO
In the chemical formula for ammonia, NH3, what does the subscript 3 represent?
The number of nitrogen and hydrogen atoms in each molecule of ammonia
The number of hydrogen atoms in each molecule of ammonia
The number of ammonia molecules that will bond together
The number of nitrogen atoms in each molecule of ammonia
Which picture illustrates the structure of a molecule of water?
Which of these can be separated using a magnet?
A mixture of sand and salt
Rust formed from iron and oxygen
A compound of hydrogen and sulfur
A mixture of sand and bits of iron
Compounds are made up of more than one element. Which of the following represents a compound?
H2
NH3
O3
N2
Which of the following materials is composed of only one type of atom?
Water
Helium
Air
Sugar
A student first dissolves sugar in water, then evaporates the water to make rock candy. The sugar water is an example of —
an atom
an element
a compound
a mixture
Which of these is a compound?
Oxygen in the air
Liquid nitrogen
Neon in lights
Carbon dioxide gas
Which of these cannot be separated into its parts by an ordinary chemical or physical process?
A mixture of salts (NaCl, KI)
A compound of nitrogen (NH3)
An atom of carbon (C)
Which of these best shows particles in a mixture?
A compound is a molecule made up of atoms from at least two elements.
Which of the following gases is a compound?
Ozone (O3)
Oxygen (O2)
Methane (CH4)
Nitrogen (N2)
Several centuries ago, men called alchemists tried to transform common metals into gold. Even though they tried many different chemical and physical methods, they never succeeded because —
they could not heat common metals to
extremely high temperatures
the common metals they worked with
were not pure
they did not add the correct material to
the common metal
elements cannot be changed to other
elements by physical or chemical
means
Which of these is best classified as a mixture?
Carbon dioxide
Water
Soil
Iron
A substance made up of two or more elements that have been chemically combined is called —
an atom
a compound
an element
a mixture
Because zinc can combine with other substances but cannot be changed into a simpler substance by an ordinary chemical process, zinc is classified as —
a compound
a mixture
an element
an acid
A mixture of iron filings and sulfur can easily be separated by —
placing the mixture in water
performing a chemical reaction
heating the mixture
using a magnet
