WorksheetsCounting Atoms and Chemical Reactions
Total questions: 17
Worksheet time: 16mins
Serotonin is a chemical substance that acts as a neurotransmitter. It helps relay messages in the human brain. The formula for one molecule of serotonin is shown below.
C10H12N2O
How many atoms in all are in a molecule of serotonin?
1
4
25
24
Identify the reactants in the chemical equation below.
NaOH + HCl --> NaCl + H2O
NaCl and H2O
HCl and NaCl
NaOH and HCl
HCl and H2O
Which of the following chemical equations is balanced?
3Na + Cl2 --> 3NaCl
CO2 + H2O --> C6H12O5 + O2
2H2O + O2 --> 2H2O + OH
3AgBr + GaPO4 --> Ag3PO4 + GaBr3
The formula for Glucose is C6H12O6. How many atoms does glucose contain?
6
12
24
48
How many copper (Cu) atoms are there in the Cu(NO3)2 molecule below?
Cu + 2AgNO3 ---> 2Ag + Cu(NO3)2
6
1
5
2
A student mixes two solutions (liquids), planning to produce carbon dioxide. Which of the following is the BEST evidence that a chemical reactions as taken place and carbon dioxide (gas) has been formed.
Color Change
Temperature Change
Formation of bubbles
formation of a solid
How many atoms are in one molecule of baking soda, NaHCO3?
12
4
6
5
Which of the following are types of evidence that tells us a chemical change has taken place?
CLICK ALL THAT ARE CORRECT!
Color change
Light is produced
The substance breaks into tiny pieces
Temperature change
Bubbles are formed
When two liquids are mixed together and a solid is formed, what do we call it?
Metal
A rock
Precipitation
Precipitate
Which of the following lists all of the elements that are present in a molecule of potassium carbonate, K2CO3?
Phosphate and calcium
Potassium, carbon, and oxygen
Argon and Oxygen
Phosphorus, oxygen, and calcium
The chemical formula for sodium is Na2SO4. How many sulfur atoms are in the formula for sodium sulfate?
6
2
1
7
Which of the following equations follows the law of conservation of mass?
2Na + Cl --> NaCl
C2H4 + 3O2 --> 2CO2 + 2H2O
C + 4H2 --> CH4
3H2O --> 3H2 +3O2
What would be the chemical formula for the molecule above
CH8
C8H
CH4
C4H
Which of the following would be evidence that a chemical change took place?
Click all that apply.
A solid melts at 200oC
A precipitate is formed
A rock breaks in half
Sugar Dissolves in Kool-Aid
Light and heat are produced when a log burns
What does the Law of Conservation of Mass state?
matter can always been created
matter is always destroyed
matter cannot be created or destroyed
Matter can be destroyed, but never created
Products are found on what side of the arrow?
Right
Left
Reactants are found on which side of the arrow?
Right
Left
