WorksheetsUnit 2 - Chemical Equations and Chemical Reactions
Total questions: 45
Worksheet time: 2hrs 30mins
This image shows the product of a chemical reaction. Which is the name of the kind of solid substance formed in this type of chemical reaction?
aqueous
precipitate
acid
synthesis
Which example provides evidence that a chemical reaction has occurred.
dissolving
melting
formation of a gas
bending
4Ca(OH)2
Which of the following describes a chemical change?
water freezes to form ice
sugar dissolves in water
gasoline burns in a car engine
a piece of metal expands when it is heated
What type of change occurs when a new substance is formed that has properties different from those of the original substances?
chemical change
nuclear change
physical change
mutation
Which of the following describes a chemical change?
cutting a piece of paper with scissors
cooling a mixture of air and kerosene vapor to obtain liquid kerosene
burning a piece of notebook paper in the presence of oxygen
heating water over a flame to its boiling point
In every chemical reaction, the mass of the products is always ____________________________.
slightly less than the mass of the reactants
much less than the mass of the reactants
the same as the mass of the reactants
greater than the mass of the reactants
How many carbon atoms are present in this chemical equation?
1
2
3
4
The left side of this equation is called ________________.
products
reactants
The right side of this equation is called ________________.
products
reactants
A number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant or product are involved in a reaction is called __________________________________.
coefficient
reactant
subscript
product
CaCO3 represents a chemical _______________.
symbol
formula
subscript
reaction
In chemical reactions, what does the Law of Conservation of Mass mean?
Matter is not created or destroyed.
The total mass of the reactants is greater than the total mass of the products.
The total mass of the reactants is less than the total mass of the products.
Matter is not changed.
How many oxygen atoms are in the molecule 2C2HO8Cl2?
2
16
8
5
How many hydrogen atoms are in the compound NH3O5?
3
4
5
1
What is the left side of a chemical equation called?
reactant
product
yields
chemical equation
What is the total number of atoms present in 5Na3PO4?
5
40
55
8
What is the little number found after an element symbol in a chemical formula called?
coefficient
subscript
atom
equation
Is this chemical equation balanced?
Yes
No
Which term best describes this substance?
element
compound
mixture
a mixture of compounds
Which term best describes this substance?
element
compound
mixture
a mixture of elements
Which compound has twice as many oxygen atoms as hydrogen atoms?
H3PO4
H2SO4
HClO3
H2O
Is this a chemical change or a physical change?
chemical change
physical change
What are the blue numbers called?
oxidation numbers
subscripts
group numbers
product numbers
How many molecules are shown in this chemical formula?
1
2
3
4
In a chemical reaction, Reactant A has 5 g and Reactant B has 9 g. How many grams should Product C have?
4 g
5 g
9 g
14 g
In a chemical reaction, Reactant A has 5 g and Product C has 9 g. How many grams should Reactant B have?
4 g
5 g
9 g
14 g
If a substance is a compound, it is also a __________________.
molecule
mixture
element
secret
Elements are represented by chemical symbols. Chemical symbols are written with _____________________________.
all lower case letters
all capital letters
using the 1st letter of the name
at least one capital letter
Which description best represents the substance in the image?
element
compound
mixture
mixture of compounds
Strontium phosphate, Sr3(PO4)2, is a crystalline substance used in medicine and industry. How many phosphorus atoms are represented in the formula for this compound?
2
3
4
8
The table shows the chemical formulas of four substances. Which substances have the same number of carbon atoms?
substances 1 and 2
substances 2, 3, and 4
substances 2 and 3 only
substances 1 and 3
Which of these formulas contain equal numbers of nitrogen atoms?
Formulas I and III
Formulas I and IV
Formulas II and III
Formulas I, II, and V
This equation represents a chemical reaction that occurs in living cells. How many atoms are represented in this chemical equation?
6
12
24
36
In which of these compounds are there twice as many oxygen atoms as hydrogen atoms?
H3PO4
H2SO4
HClO3
H2O
The chemical formula for sodium sulfate is Na2SO4. How many sulfur atoms are in the formula for sodium sulfate?
1
2
6
7
Serotonin is a chemical substance that acts as a neurotransmitter. It helps replay messages in the human brain. The formula for one molecule of serotonin is C10H12N2O. How many atoms are in one molecule of serotonin?
4
15
24
25
Which information could a student determine from only the chemical formula of a protein?
the color of the protein
the number of molecules in each sequence that makes up a protein
the physical arrangement of atoms in the structure of the protein
the number of atoms of each element in the protein
How many atoms of oxygen are in a molecule of glucose (C6H12O6)?
3
24
6
1
A student obtains two strips of magnesium, Mg, ribbon that are each 3 cm long. One strip of magnesium is placed in a test tube containing 5 mL of water, and the other strip is placed in a test tube containing 5 mL of hydrochloric acid, HCl. Both liquids area at room temperature. The student's observations are recorded in the table. Which statement is not supported by the students' observations?
A chemical reaction takes place between magnesium and hydrochloric acid.
A gas is released in Test Tube 2.
The substances in both test tubes are reactive only as high temperatures.
Energy is released in the reaction involving hydrochloric acid.
A scientist performed four investigations using eight different liquids. In each investigation, the scientist combined two of the liquids under a fume hood and recorded observations in the table. In which investigation is it least likely that the liquids reacted chemically?
1
2
3
4
All of the following chemical equations are correctly balanced except ______________________.
2C2H2 + 5O2 → 4CO2 + 2H2O
4Fe + 3O2 → 2Fe2O3
NaHCO3 → Na2CO3 + H2O + CO2
2CH3OH + 3O2 → 2CO2 + 4H20
