WorksheetsUnit 7 Test Review
Total questions: 40
Worksheet time: 20mins
Rust is a compound with the formula Fe2O3. What elements combine to form rust?
iron and water
iron and oxygen
iron and air
iron and acid
What number and types of atoms occur in a formula unit of Ca(NO3)2?
1 carbon atom, 1 neon atom, and 6 oxygen atoms
1 calcium atom, 2 neon atoms, and 3 oxygen atoms
1 carbon atom, 1 nitrogen atom, and 3 oxygen atoms
1 calcium atom, 2 nitrogen atoms, and 6 oxygen atoms
How many atoms are in one formula unit of the compound FeC5O5?
5
11
15
26
How many atoms of carbon are included in one formula unit of the compound Na2C2O4?
2
4
6
8
The compound potassium sulfate, K2SO4, is composed of
2 atoms of potassium, 1 atom of sulfur, and 4 atoms of oxygen.
2 atoms of potassium, 4 atoms of sulfur, and 4 atoms of oxygen.
two molecules of potassium and one molecule of sulfate.
one molecule of potassium and two molecules of sulfate.
How many atoms are in one formula unit of magnesium hydroxide, Mg(OH)2?
3
4
5
6
The chemical formula for water is H20. What does the formula show about each element in the compound?
the number of valence electrons
the charge of the compound
the mass of protons in each atom
the number of atoms of each element
The periodic table provides information about the atoms of different elements . Which is a characteristic of an atom determines what element it is?
number of neutrons
number of protons
state of matter
atomic mass
In the late 1700s, Antoine Lavoisier performed a series of experiments to find out what happened when a substance burned. In each experiment, he observed that the weight of the container and its contents was the same at the end of the experiment as the beginning. These observations led him to propose the law of
combustion.
fixed proportions.
conservation of mass.
conservation of energy.
A science class is studying the states of matter. One group of students freezes 100 grams (g) of water in a cup. Another group of students melts 50g of ice in a cup. Which of these will most likely occur at the end of the experiment?
The temperature of both cups will be the same.
Both samples in the cups will be in the same state.
Both groups will have the same mass with which they started.
The time required for the changes in states of matter will be the same.
Which statement below correctly describes water?
Water is a an ionic crystalline compound.
The atoms in a water molecule are bonded covalently.
A sample of water has a definite volume and a definite shape.
A water molecule consists of two atoms of hydrogen and two atoms of oxygen.
When a neutral atom gains or loses electrons, it becomes
more stable.
an isotope.
an ion.
less charged.
How many atoms of oxygen are in a molecule of glucose, C6H1206?
1
6
12
24
Casey placed 25 grams of ice into a dry, 100-gram container. The top of the container was attached tightly. When the ice was completely melted, the student measured the mass of the container with the liquid water. What should the mass of the liquid water in the container be?
25 grams
165 grams
100 grams
200 grams
You observe a chemical reaction that has only one product. What type of reaction is it?
synthesis
decomposition
single replacement
double replacement
How does the concept of conservation of mass apply to chemical reactions?
The reactants and products have exactly the same atoms.
The reactants and products have exactly the same molecules.
The change in the amount of matter is equal to the change in energy.
The change in the amount of matter is only a small percentage of the total mass.
A beaker contains a sample of water with a mass of 325 grams. The water is boiled and weighed again after it cools. The new mass of the water is 305 grams. In this example of the conservation of matter in physical changes,
the mass is less after it cools because water has less mass as a gas.
the mass of the water was 305 grams and the mass of the water vapor was 20 grams.
the process of boiling destroyed 20 grams of the water and left 305 grams of water.
the heat energy created by boiling water makes up the rest of the mass.
What type of chemical reaction occurs when one compound breaks down and forms two or more substances?
synthesis
decomposition
single replacement
double replacement
What type of chemical reaction occurs when one element replaces another element in a compound?
synthesis
decomposition
single replacement
double replacement
What type of chemical reaction occurs when the negative ions in two compounds switch places, forming two new compounds?
synthesis
decomposition
single replacement
double replacement
What type of chemical reaction is this?
synthesis
decomposition
single replacement
double replacement
What type of chemical reaction is this?
synthesis
decomposition
single replacement
double replacement
What type of chemical reaction is this?
synthesis
decomposition
single replacement
double replacement
What are the two types of energy that are released during combustion?
thermal and light
nuclear
gravitational
sound
What type of chemical reaction is this?
synthesis
decomposition
single replacement
double replacement
Is this equation balanced or unbalanced?
H2 + O2 --> H2O
balanced
unbalanced
Is this equation balanced or unbalanced?
2Fe2O3 + 3C --> 4Fe + 3 CO2
balanced
unbalanced
What is the Law of Conservation of Mass?
Mass is not created or destroyed
New chemicals formed from a chemical reaction have a larger overall mass than original reactants
Mass is created in a physical change
Mass is created in a chemical reaction
Matter can not be created nor destroyed: it can only be
Destroyed a little bit
Invisible
Transformed or changed
None of the above
How many nitrogen atoms does N3H4O6 have?
3
4
5
6
Which chemical equation is balanced?
CH₄+O₂------CO₂+2H₂O
H₂+O₂-----2H₂O₄
4Al+3O₂-----2Al₂O₃
Which is true of the law of conservation of mass?
The amount of matter changes when reacted or changed.
The mass of all reactants are changed during a physical or chemical change.
The mass of the reactants equals the mass of the products.
The mass of the products is different than the mass of the reactants.
The mass after a physical change, such as ice melting into water, stays the same.
True
False
What are the starting substances in a chemical reaction?
reactants
products
coefficient
subscript
What are the substances that are produced by a chemical reaction?
reactant
product
coefficient
subscript
What is the number that is placed in front of an element or chemical formula in an equation?
reactant
product
coefficient
subscript
Two kilograms of water are placed in a closed container. The container is placed in the freezer, and after a few hours it turns into ice. Which is most likely the mass of the ice?
1.0 kilogram
1.5 kilograms
2.0 kilograms
2.5 kilograms
How many elements are in the compound C2H8O ?
1
2
3
4
How many total atoms are in the compound C2H8O ?
1
2
8
11
How many sodium atoms are in 6NaCl?
1
3
6
9
