WorksheetsChemical Reactions Review
Total questions: 40
Worksheet time: 40mins
Strontium phosphate, Sr3(PO4)2 is a crystalline substance used in medicine and industry. How many phosphorus atoms are represented in the formula for Sr3(PO4)2.
2
3
4
8
The table shows the chemical formulas for 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 the following diagrams illustrates a compound?
The formula for glucose is C6H12O6. How many elements does glucose contain?
1
3
24
432
The formula for glucose is 6C6H12O6. How many molecules of glucose does this formula show?
1
6
12
36
Which of the following is correct?
reactants ← products
reactants products
reactants → products
reactants = products
In the chemical equation, the large numbers in front of 12O2 represent —
numbers divisible by the subscript
the amount of energy in that substance
the number atoms of each element in the molecule
the number of molecules of that substance in the reaction
How many copper (Cu) atoms are there in Cu(NO3)2 ?
1
2
5
6
How many Nitrogen atoms (N) are in the formula shown?
1
2
3
6
How many Oxygen atoms (O) are in the formula shown?
2
3
6
12
During an investigation, a student combined the two clear, colorless solutions shown below.
The student observed that the temperature changed from 25°C to 23°C when the solutions were combined and that a white substance rapidly formed and settled to the bottom of the container. What most likely happened to produce these results?
One of the original compounds came out of solution.
The solutions reacted chemically.
Some of the water froze into ice crystals.
Rapid evaporation of water occurred, leaving a solid.
A student added yeast and sugar to lukewarm water and placed it in a flask. She stretched a balloon over the opening of the flask. After several minutes, she noticed small bubbles rising along the side of the flask as the balloon slowly began to inflate. The student concluded that —
A physical change was occurring.
The water, sugar, and yeast were products of a chemical reaction.
The bubbles indicated a chemical change.
The strong smell was evidence of a physical change.
All of the arrows indicate —
chemical changes
irreversible changes
physical changes
continuous change
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.
Is the following equation balanced or unbalanced?
P4 + 3Br2 --> 2PBr3
Balanced
Unbalanced
Balanced or Unbalanced?
CH4 + 2O2 ---> CO2 + 2H2O
Balanced
Unbalanced
Balanced or Unbalanced?
NaBr + CaF2 -----> NaF + CaBr2
Balanced
Unbalanced
Balanced or Unbalanced?
NaBr2 + CaF -----> NaF + CaBr2
Balanced
Unbalanced
The arrow in a chemical equation represents the ...
subscript
coefficient
chemical reaction
phase change
Which is not true about the law of conservation of mass?
Nothing is created
The same number of atoms are in both the products and reactants
New atoms are created when a new substance is formed
Nothing is destroyed
Which compounds represent the product(s) in the following equation?
C3H8 + 5O2 ----> 4H2O + 3CO2
C3H8
5O2
Only 4H2O
Both 4H2O and 3CO2
Which compounds represent the reactants in the following equation?
C3H8 + 5O2 ----> 4H2O + 3CO2
Only 5O2
4H2O
Both C3H8 and 5O2
Both H2O and CO2
A compound secreted by honeybees to paralyze intruders in their hive is known as 2-heptanone. The formula for this compound is shown.
CH3C4H8COCH3
How many atoms of each element are in one molecule of 2-heptanone?
4 carbon atoms, 11 hydrogen atoms, and 1 oxygen atom
7 carbon atoms, 11 hydrogen atoms, and 8 oxygen atoms
6 carbon atoms, 14 hydrogen atoms, and 3 oxygen atoms
7 carbon atoms, 14 hydrogen atoms, and 1 oxygen atom
Barium sulfate, BaSO4, is a white crystalline solid that is insoluble in water. It is used by doctors to diagnose problems with the digestive system. Barium hydroxide, Ba(OH)2, is also a white crystalline solid and is used in wastewater treatment.
How many more oxygen atoms are represented in the formula for barium sulfate than in the formula for barium hydroxide?
(a)
Which statement best describes evidence that a chemical reaction occurs as bread bakes?
The water in the bread dough evaporates.
The bread rises as gas bubbles form in the baking bread.
The bread takes the shape of the container in which it is baked.
The water in the bread dough is used to keep the bread moist as it bakes.
Is this equation balanced?
(Are there the same amount of H and O atoms on both sides of the equation?)
H2O2→ H2O + O2
Yes
No
A precipitate is
Rain
Snow
A solid formed in a chemical reaction
Condensation formed in a chemical reaction
In a chemical reaction, no new atoms are created, and no atoms are destroyed.
Look at the chemical equation.
How many atoms of mercury (Hg) are in the reactants?
(a)
Look at the chemical equation.
How many atoms of oxygen (O) are in the products?
(a)
Look at the chemical equation.
How many atoms of nitrogen (N) are in the reactants?
(a)
Look at the chemical equation.
How many atoms of oxygen (O) are in the products?
(a)
Look at the chemical equation.
Is it written correctly to show the Law of Conservation of Mass?
Yes
No
A chemical change is different than a physical change because in a chemical change
chemicals are used
molecules do not physically touch
a new substance is formed and in a physical no new substance is formed
the change can be seen but in a physical change it cannot
A change in the shape of an object is an example of _________________.
a chemical change
energy
an endothermic change
a physical change
