WorksheetsChemical Reactions and Changes Quiz
Total questions: 104
Worksheet time: 1hrs 5mins
During a science experiment, Diomar and Aubrie were observing a chemical reaction. They noticed that when they added a certain enzyme, something happened to the reaction. What effect do you think the enzyme had on the chemical reaction?
C. It changed the color of the reaction mixture
B. It sped up the reaction
A. It increased the temperature
Max, Diomar, Johan, and Aubrie are working on a science project. They are trying to write the balanced equation for the reaction that occurs when glucose and oxygen react to form carbon dioxide and water. Can you help them?
A. C6H12O6 + 0₂ → 6CO₂ + 6H2O
C. C6H12O6 + 0₂ → 3CO₂ + 3H2O
B. C6H12O6 + 0₂ → 2CO₂ + 2H2O
Johan, Max, Diomar, and Aubrie are discussing about different properties of substances. Johan says density is a chemical property, Max says boiling point is a chemical property, while Diomar says flammability is a chemical property. Who is correct?
Johan (density)
Max (boiling point)
Diomar (flammability)
Johan and Max are in a science class. Their teacher, Diomar, gives them a material and asks them to observe it without changing the identity of the substances that make up the material. This is known as a
A. chemical property
B. physical property
C. chemical change
During a science experiment, Aubrie, Diomar, Max, and Johan were studying the effect of various substances on the speed of chemical reactions. They came across a substance called 'enzyme'. What is an enzyme according to their findings?
C. A substance that speeds up chemical reactions
B. A substance that has no effect on chemical reactions
A. A substance that slows down chemical reactions
Aubrie and Diomar are conducting a chemistry experiment in their school lab. They noticed that the total mass of the reactants before the experiment is the same as the total mass of the products after the experiment. Which law does this observation illustrate?
Mass can be created or destroyed in a chemical reaction
The law of conservation of mass, which states that the total mass before a chemical reaction is the same as the total mass after a chemical reaction
Every reaction creates an equal amount of mass related to the amount of energy required for the reaction
The total amount of mass is equal to the volume of both chemicals in the reaction
During a science experiment, Max and Johan observed that when sugar was heated until it caramelized, its identity changed. Is this observation correct?
True
False
During a science experiment, Max and Johan observed different processes. Which of the following processes observed by them is an example of a chemical change?
Max bending a soda can
Johan observing the evaporation of milk
Aubrie watching the melting of wax
Diomar noticing the burning of paper
During a cookout, Johan observed several changes. Which of these changes observed by Johan is an example of a chemical change?
Max's magnet sticking to the fridge
Dew disappearing from the grass where Diomar was sitting
Aubrie mashing potatoes
Frying a hamburger on the grill
During a camping trip, Diomar decided to light a match to start a fire. Max dissolved some salt into water to make a saline solution for cooking. Johan froze some water to make ice cubes for the cooler. Aubrie accidentally broke a glass while setting up the camp. Which of these is an example of a chemical change?
Diomar lighting a match
Max dissolving salt into water
Johan freezing water
Aubrie breaking a glass
During a science experiment, Johan mixed two chemicals. He observed a change in color, a distinct odor, and the mixture started giving off light. This is evidence of what?
Physical change
Chemical change
Biological change
None of the above
Diomar, Johan, Max, and Aubrie are at a camping trip. They are given a piece of paper and asked to cause a chemical change. What should they do?
crumble it
burn it
leave it out in the sun
draw on it
During a cooking class, Johan, Aubrie, Diomar, and Max are making a pizza. Which process involves a chemical change?
Johan mixing spices for the sauce
Aubrie slicing pepperoni for the topping
Diomar spreading cheese on the pizza
Max baking the dough to form the crust
During a winter night, Johan noticed that the water pipe in his backyard froze and cracked. Max, on the other hand, observed that a penny he lost in the grass slowly changed color. Diomar saw a log giving off heat and light as it burned in his fireplace. Aubrie noticed that a tree in her garden was storing energy from the Sun in its fruit. Which of these is an example of a physical change but not a chemical change?
Diomar's log giving off heat and light as it burns.
Aubrie's tree storing energy from the Sun in its fruit.
Max's penny lost in the grass slowly changing color.
Johan's water pipe freezing and cracking on a cold night.
Aubrie, Diomar, Max, and Johan were conducting a science experiment. They noticed that in every chemical change they observed, one characteristic was always present. Which of the following is that characteristic of all chemical changes?
A different state of matter is produced.
Some mass is converted to energy.
Some form of light is given off.
A new material is formed.
Diomar and Aubrie are conducting a science experiment in their school. They mix H20 (water) and CO2 (carbon dioxide) and observe that it produces C6H12O6 (glucose) and O2 (oxygen).
Can you identify the reactants in their experiment?
H20 + CO2
C6H12O6 + O2
→
H20 + CO2→ C6H12O6 + O2
Johan was conducting a science experiment in his lab. He mixed a solution and observed the following chemical reaction:
H2O2 → H2O + O2
What are the products of Johan's experiment?
H2O2
H2O + O2
H2O2→H2O + O2
During a cooking class, Aubrie and Max were given different tasks. In which of the following tasks has a chemical reaction occurred?
Aubrie put liquid pancake batter into a hot pan, the batter solidified and began to turn brown.
Max turned on a blender filled with fruits, the fruit was chopped up and mixed together.
Diomar took a tray filled with ice cubes out of the freezer, the cubes began to melt.
Johan added a spoonful of sugar to a mug of hot coffee, the sugar dissolved completely.
Diomar and Johan were conducting a chemistry experiment. According to the Law of Conservation of Mass they observed that,
matter is always created in a chemical reaction
matter is always destroyed in a chemical reaction
matter is created and then destroyed in a chemical reaction
matter is not created or destroyed in a chemical reaction
The law of conservation of mass can be demonstrated by a chemical reaction. Which of the following models of a chemical reaction best represents the law of conservation of mass?
Johan accidentally spilled a substance on his lab table. If the substance is corrosive, what does it mean?
The substance is able to be burned
The substance is able to be eaten
The substance is able to cause damage
The substance is able to go through a chemical reaction
During a science experiment, Johan and Aubrie noticed that atoms ____________ to form new substances.
Change
Switch
Turn into new atoms
Rearrange
Diomar, Aubrie, Max, and Johan are studying chemistry. They are trying to identify an example of a certain structure. Johan suggests that a diamond is an example of what?
Atom
Molecule
Extended Structure
Cube
Aubrie and Diomar were discussing about water and oil. They concluded that these are different substances because they have different:
Sizes
Properties
Atoms
Tastes
Johan and Diomar were discussing about a science experiment. Johan said, 'Can a chemical reaction happen with just one substance, like when water separates into H and O?'
Yes! Aubrie also saw water separate into H and O in the lab!
No! Max thinks that is crazy!
During a science project, Max and Johan discovered a brown substance in the water sample they collected from Westfield's local pond. What could this substance be?
Iron
Salt
Rust
Nobody knows!
Johan, Diomar, Aubrie, and Max are discussing the properties of a substance. They all agree on the melting point, boiling point, and color of the substance. However, Max thinks that 'Phase' is not a property of the substance. Is Max correct?
Melting point
Boiling point
Color
Phase
Will these two samples of substances collected by Johan and Max have different properties?
Yes, because they have different groups of atoms
Yes, because there are more of Max's sample
No, but they both have 2 atoms in each molecule
No, because they both have purple atoms
Diomar and Aubrie are in a science class. They are curious if a chemical reaction will happen whenever they mix two substances together. What do you think?
Yes, always
No, only if heat is involved
No, it depends on the two substances
Yes, because anytime you mix something a chemical reaction happens
Johan and Aubrie are conducting a chemistry experiment. They are curious to know if during their chemical reaction, the atoms change from one type to another. What would you tell them?
Yes, that is how new substances are formed
No, atoms never change type
Yes, sometimes
No, they just change phase
Max, Aubrie, Diomar, and Johan are in a chemistry class. They are discussing about groups of atoms joined together in a particular way. What do they call this?
Extended structure
Molecule
Substance
Fertilizer
Aubrie and Diomar are in a chemistry lab. They are asked to identify something that is made of all the same atoms or groups of atoms. What could it be?
Substance
Product
Molecule
Extended structure
Johan, Aubrie, Diomar, and Max are discussing about what all the stuff in their science project is made of. What do you think they concluded?
Atoms
Germs
Bacteria
Cells
Diomar and Johan are discussing about different substances. Diomar says that boiling point, melting point and density are physical properties of a substance. Johan says that flammability is also a physical property. Who is correct?
Only Diomar is correct
Only Johan is correct
Both Diomar and Johan are correct
Neither Diomar nor Johan is correct
During a science experiment, Max and Diomar observed that two physical properties occur at the same temperature. Can you identify which two properties they observed?
freezing point of a substance
boiling point of a substance
melting point of a substance
liquification of a substance
During a science experiment at school, Aubrie and Johan placed a sample of lithium into a container of water. They observed the lithium floating and making a buzzing sound as gas bubbles were forming around it. Max, their teacher, asked them to draw a conclusion from this observation. Which conclusion is BEST supported by this observation?
A chemical change took place.
The lithium was dissolved by the water.
Dissolved gases were released.
Water was vaporized.
Johan, Diomar, Aubrie, and Max are studying for their chemistry exam. They are discussing the elements in the rightmost column of the periodic table. What physical property is characteristic of all these elements that Max pointed out?
They have a very high melting point
They are in a gas state at room temperature
They are good conductors of electric current
They are extremely brittle solids at room temperature
Johan and Aubrie are baking a cake. They are curious about how the concept of conservation of mass applies to their baking process. Can you explain it to them?
The ingredients they started with and the cake they end up with have exactly the same atoms.
The ingredients they started with and the cake they end up with have exactly the same molecules.
The change in the amount of matter in the cake is equal to the change in energy.
The change in the amount of matter in the cake is only a small percentage of the total mass.
Johan and Max were conducting a science experiment. They observed a few changes during the experiment. According to you, which observation is the BEST evidence that a chemical change has occurred?
Johan noticed a change of state in the substance
Max felt a release of energy during the experiment
Diomar recorded a temperature change in the substance
Aubrie observed the formation of a new substance
Why must the law of conservation of mass be done in a closed system?
THROWBACK- Johan and Max went on a fishing trip. They noticed the water in the lake was not clear. Turbidity measures how (a) the water is.
Max, Diomar, Johan, and Aubrie are conducting a science experiment. They have a solution with a pH value between 1 and 6. What type of solution is this (acid or a base)?
(a)
Diomar and Max decided to share their lunch. They divided their food in such a way that they both got equal amounts. This situation can be best described as:
balanced
coefficient
equation
product
Aubrie and Diomar are playing a game where they have to make two groups of objects equal. What is this called?
balanced
reactant
equation
odor
During a science experiment, Aubrie noticed a particular smell when she mixed two chemicals. What is another term for this smell?
matter
odor
substance
mass
Johan has a math test tomorrow. He has been studying hard and believes he has found something that shows his theorem is true. What is this called?
equal
statement
sign
proof
Diomar was chosen to ______ his school in the inter-school debate competition.
represent
result
chemical
property
Aubrie, Diomar, Max, and Johan decided to pool their money together to buy a gift. What is the result of adding all their contributions together?
substance
balance
sum
letters
During a science experiment, Aubrie mixed two substances and observed that they changed into a different substance with different chemical and physical properties. What is this process called?
proof
equation
chemical change
odor
Aubrie and Diomar conducted a chemistry experiment in their school lab. They observed that the total mass of the substances they used before the experiment was the same as the total mass of the products after the experiment. This is an example of what?
A chemical reaction
A substance
A product
The law of conservation of mass
During a science experiment, Aubrie and Diomar mixed atoms of one or more substances and observed that they rearranged to form one or more new substances. What is this process called?
mass
chemical
chemical reaction
formula
The starting substances in a chemical reaction.
equation
reactants
mass
reaction
The substances produced by the chemical reaction.
Products
law
reaction
substances
A number placed in front of an element symbol or chemical formula in an equation.
odor
property
coefficient
product
................... is a description of a reaction using element symbol and chemical formula
a chemical equation
a chemical structure
In a chemical equation, on what side of the arrow are the reactants?
right
left
In a chemical equation, on what side of the arrow are the products?
right
left
True or False? During a chemical reaction a new substance (or substances) is produced.
True
false
Count the total number of atoms in the chemical formula: 5H2O2
5
8
10
20
Identify the total number of molecules in the chemical formula: 6CH4
5
10
6
20
.
Which of the following can be changed to balance a chemical equation?
products
element symbols
coefficients
subscripts
.
A chemical equation is balanced when the number of each type of __________ is the same on both sides of the yield sign.
compound
molecule
atom
fotmula
Which of the following equations is balanced?
2H2 + O2 ---> H2O
H2 + 2O2 ---> 2H2O
H2 + O2 ---> H2O
2H2 + O2 ---> 2H2O
Which coefficient will balance the following equation?Zn + ___ HCl --> ZnCl2 + H2
2
4
6
3
How many atoms of hydrogen are in the following chemical formula? 3Mg(OH)2
5
6
1
2
Which coefficient will balance the following equation? ____ Ca + N2 → Ca3N2
6
3
2
8
What is a coefficient?
The large number to the left of a chemical formula.
The small number on the left of a chemical symbol
Which chemical equation is balanced?
Li + F2 → 3LiF
2Li + F2 → 2LiF
2Li + F2 → LiF
What is the total number of atoms present in 5Na3PO4?
5
40
60
55
How many atoms of aluminum are on each side of the yield sign in the following equation? 4Al + 3O2 --> 2Al2O3
2
1
6
4
Is the following equation balanced or unbalanced? Fe + S --> FeS
True
False
Which of the following is the correct balanced equation for the unbalanced equation shown? ____ H2 + ____ Cl2 --> ____ HCl
2H2 + Cl2 --> 4HCl
H2 + Cl2 --> 2HCl
What is the part of the chemical equation in green called? Fe + S --> FeS
products
reactant
What is the part of the chemical equation in green called? H2 + O --> H2O
reactants
product
(a) can be observed without changing the object or matter.
Chemical Properties
Chemical Changes
Physical Changes
Which of the following is an example of a physical property?
Reactivity with other chemicals
Flammability
Toxicity
Color
What is a physical change?
A change in color, odor, or temperature
A change in the molecular composition of a substance
A change in state from solid to liquid
A change in reactivity with other chemicals
(a) Physical Changes are reversible
(a) cannot be determined by touching or viewing a sample, they can only be observed by
changing the substance.
Chemical Changes
Physical Changes
Which of the following is a chemical property?
Density
Brittleness
Oxidation
Solubility
What is a chemical reaction?
A change in color, odor, or temperature
A change in state from solid to liquid
A process where new substances are formed
A process where physical properties are altered
What are the signs that a chemical reaction has occurred?
(Select all that apply)
Change in color, odor, or temperature
Formation of bubbles or gas
Production of light
Volume
Are all chemical reactions violent and explosive?
Yes, all chemical reactions are violent and explosive
No, chemical reactions can be slow and nonexplosive
Only reactions involving gases are violent and explosive
Chemical reactions are always unpredictable
There are 3 signs that indicate a chemical reaction occuring (a) , (b) , and (c)
When a gas escapes from a chemical reaction it can be often seen as (a) .
What best describes the law of conservation of mass?
Matter can be created or destroyed
Matter cannot be created or destroyed
Matter can be destroyed but not created
Matter can change form and be destroyed
Match the following images to the correct vocabulary
Physical Change
Chemical change
Chemical Property
Physical Property
A green powder is heated & a gas is given off while it turns to a black solid. This describes
Physical Change
Chemical Change
Change in State
Change in Temperature
A Chemical Change is also known as what?
Physical Change
Physical Property
Chemical Reaction
Chemical Property
Which of the following could indicate that a chemical change took place?
Change in color
Production of Energy
Formation of Gas
All are correct
The formation of a solid when two liquids combine is called?
Solidification
Freezing
Precipitate
Solubility
The difference between a Physical change and a Chemical change is…
Physical change is only a change to the outside appearance.
Chemical change is when matter is changed into something new.
Atoms are rearranged in chemical changes & not in physical.
All are correct.
What does a chemical change result in?
A change in state of the substance (ex. liquid to solid)
A change in texture of the substance.
A change in the way atoms are bonded to each other.
A change in the appearance of the substance.
Which type of change is most often easily reversed?
Chemical
Physical
Both a physical and chemical change.
Neither a physical or chemical change.
Identify what type of change happening in the picture below...
Chemical Change
Physical Change
Endothermic Reaction
Exothermic Reaction
Identify what type of change happening in the picture below...
Chemical Change
Physical Change
Endothermic Reaction
Exothermic Reaction
Identify what type of change happening in the picture below...
Chemical Reaction
Physical Change
Change in State
Change in appearance only
If the chemical properties of a substance remain unchanged & the appearance or shape of an substance changes it is a...
Chemical Change
Physical Change
Both a physical and chemical change.
Neither a physical or chemical change.
Which of the following is an example of a physical change?
A glass falling and shattering on the floor.
Baking a birthday cake.
Burning a piece of paper.
Baking soda and vinegar mixing together.
When a new substance is formed with different properties than the original substance it is called a...
Chemical change
Physical change
Change in State
Change in appearance only.
Which type of change are irreversible?
Chemical Changes
Physical Changes
Changes in State
Changes in Temperature
Which is not a clue that could indicate a chemical change has occurred?
Change in color
Change in shape
Release of energy
Formation of an odor
During Chemical Reactions, the new substances created are called?
Precipitate
Corrosion
Reactants
Products
During Chemical Reactions, the substances that are used are called?
Precipitate
Corrosion
Reactants
Products
