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WorksheetsChemical Reactions Review
Total questions: 40
Worksheet time: 21mins
Check all that apply.
Which of the following are examples of physical change?
Ice is placed in a pot and heated until it boils and becomes steam.
A hammer is used to break a piece of limestone into several small chunks.
A match is struck and burns with a bright light.
Mixing baking soda and vinegar together, and this causes bubbles and foam.
When a new substance is formed with different properties than the original substance it is called a _______________.
chemical change
physical change
state change
phase change
Which is NOT a clue that a chemical change has occurred?
phase change
gas release
energy release (heat, light)
color change
In a chemical reaction _____________.
the atoms of the reactants always stay together to form the products
the atoms of the reactants unbond, rearrange, and then rebond to form the products
new atoms are formed which combine to make the products
some atoms disappear while others multiply to form the products
In the diagram, letter D represents a __________________.
subscript
coefficient
product
equation
In the diagram, letter E represents a __________________.
subscript
coefficient
product
equation
Which are the reactants in the equation shown?
H2O and CO2
O2 and CH4
Which is the product in the reaction shown?
Al2O3
Al
O2
How many hydrogen atoms are shown in the reactants?
3
6
5
2
In the modern periodic table elements are arranged by the __________________.
atomic mass
atomic number
valence electrons
number of isotopes
An element's identity is determined by the number of __________________.
electrons.
protons.
neutrons.
valence.
The atoms within the same group on the Periodic Table of Elements all have the same __________________.
abbreviation
number of energy levels
number of valence electrons
number of electrons
The atoms within the same period on the Periodic Table of Elements all have the same __________________.
abbreviation
number of electron shells
number of protons
number of valence electrons
In a(n) _________________ bond, metals and nonmetals bond together.
ionic
covalent
neutral
metallic
In a(n) _________________ bond, a nonmetal will bond to another nonmetal.
covalent
ionic
neutral
metallic
The Law of Conservation of Mass states __________________.
that matter exists in all states and reacts the same
that matter can only be changed into new substances by introducing a catalyst
that matter exists in the same state throughout any chemical change
that matter cannot be created or destroyed and that the mass of the products must equal the mass of the reactants
How many aluminum atoms are in this compound? 4Al2O3
2
8
6
4
How many fluorine atoms are in this compound?
6MgF2
2
6
8
12
Which statement is NOT a description of a chemical reaction?
A solid is dropped into a beaker of liquid and a gas is released.
Two liquids are mixed in a beaker and a solid forms at the bottom of the beaker.
A solid is dropped into a beaker of liquid and an explosion occurs.
A liquid is heated in the sun and half of it evaporates.
A chemical reaction that absorbs heat is considered __________________.
Single replacement
Exothermic
Endothermic
Decomposition
A chemical reaction that releases heat is considered __________________.
Single replacement
Exothermic
Endothermic
Decomposition
When the pH of a solution becomes more acidic, the number on the pH scale __________________.
goes up
goes down
stays the same
it depends
What is needed to break bonds and is also released when bonds are broken?
Energy
Bananas
Atoms
Electrons
If two substances react and the temperature of the mixture decreases, the reaction is __________________.
Exothermic
Endothermic
Idon'tknowthermic
Nocluethermic
The purpose of a catalyst is to __________________.
speed up a reaction
slow down a reaction
create more reactants
stop the reaction
A precipitate is formed when __________________.
two liquids react and a gas is produced
one liquid dissolves in another
a solid dissolves in a liquid
two liquids react and a solid is formed
In a chemical reaction, mass is conserved. This means that __________________.
the mass of the reactants stays the same during a chemical reaction
the mass of the products stays the same during a chemical reaction
the type and number of atoms in the reactants equals the type and number of atoms in the products
the mass of the products is always twice the mass of the reactants.
The Law of Conservation of Mass can be demonstrated by a chemical reaction. Which of the following models of a chemical reaction best represents this law?
The substances that you start with in a chemical reaction are called __________________.
products
reactants
starters
enders
The substances that are formed as a result of the chemical reaction are called __________________.
products
reactants
starters
enders
How many different elements are in C6H12O6?
1
2
3
4
Which of the following is evidence that a chemical reaction has taken place?
change in state
formation of gas bubbles
something was cut in half
a mixture is formed
A scientist performed four investigations using eight different liquid substances. In each investigation, the scientist combined two of the liquids under a fume hood and recorded observations in the table below. In which investigation is it LEAST likely that the liquids reacted chemically?
1
2
3
4
If a chemical reaction starts with 20 grams of reactants, it should create how many grams of product?
a total of 40 grams of products
a total of 10 grams of products
a total of 80 grams of products
a total of 20 grams of products
Most atoms bond so that they have a total of 8 valence electrons. This means that it adheres to the _______________.
octet rule
conservation of mass
valence law
catalyst
In making a pizza, which process involves a chemical change?
mixing spices for the sauce
slicing pepperoni for the topping
spreading cheese on the pizza
baking the dough to form the crust
Which of the following is a characteristic of all chemical changes?
A different state of matter is produced.
Some mass is converted to energy.
A new material is formed.
Some form of light is given off.
A baseball strikes the roof of a car and dents it. The paint on the roof begins to crack and chip, exposing the metal. The exposed metal on the roof rusts, eventually causing a small hole in the roof. Which event is considered a chemical change?
the baseball strikes the roof
the roof of the car dents
the paint cracks and chips
the exposed metal rusts
When vinegar and baking soda are combined, bubbles begin to form. Bubbles are evidence of a chemical reaction because they _______________.
pop when they are touched
show that a gas is forming
form at a fast rate
are generally transparent
