WorksheetsPhysical and chemical reactions
Total questions: 67
Worksheet time: 34mins
Melting Ice
Physical Change
Chemical Change
Cutting Paper
Physical Change
Chemical Change
Frying Eggs
Physical Change
Chemical Change
Toasting Bread
Physical Change
Chemical Change
Burning Wood
Physical Change
Chemical Change
Rotting Fruit (Like a brown banana)
Physical Change
Chemical Change
Dissolving salt in water
Physical Change
Chemical Change
Boiling Water
Physical Change
Chemical Change
What is the process by which a chemical change occurs?
Conservation of Matter
Physical Change
Chemical reaction
Condensation
What always happens during a chemical change?
The material and its properties change
The material dissolves
The total mass of the material changes
The material changes state from a solid to a liquid
What is the best definition of a chemical change?
A change in the state of matter in which the form changes but the properties stay the same.
A change in the state of matter in which the material changes into an entirely different material with properties that are different from the original material.
A change in the state of matter in which the material is still the same just in a different form.
Which is not a sign that a chemical reaction has occurred.
A change in mass
bubbling
production of an odor or smell
change in color
Which is not evidence that a chemical reaction has occured
Production of flames
Change in temperature or heat
freezing
Production of light
Conservation of matter applies to physical and chemical changes
True
False
The total mass after a chemical reaction is that same as the total mass before a chemical reaction
True
False
The mixing of two or more substances can result in a new substance.
True
False
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 change no new substance is formed
The change can be seen but in a physical change it cannot
In a chemical reaction...
The atoms of the reactants always stay together to form the products
The atoms of the reactants unbond, rearrange, and then rebond to form the products
New atoms are formed which combine to make the products
Some atoms disappear while others multiply to form the products
In a chemical reaction, mass is conserved. This means that
The mass of the products stays the same during a chemical reaction
The mass of the products is always twice the mass of the reactants
The mass of the reactants stays the same during a chemical reaction
The type and number of atoms in the reactants equals the type and number of atoms in the products
If the reactants on the left side of a chemical equation are C3H8 + 5O2, the products in a balanced equation could be
2CO2 + 3H2O
3CO + 4H2O
3CO2 + 4H2O
4CO2 + 3H2O
If the reactants on the left side of a chemical equation are C3H8 + 5O2, the products in a balanced equation could be
2CO2 + 3H2O
3CO + 4H2O
3CO2 + 4H2O
4CO2 + 3H2O
If two substances react and the temperature of the mixture increases, the reaction is
Not one that produces anything new
Exothermic
One that needs a catalyst
Endothermic
If two substances react and the temperature of the mixture decreases, the reaction is
Endothermic
Never going to happen unless it is heated
Exothermic
one that causes atoms to be destroyed
The law of conservation of mass states
matter can not be created or destroyed
matter can be created and destroyed
matter can be changed and created
matter can be rearranged and destroyed
In the chemical reaction CH4 + 2O2 → CO2 + 2H2O, there are reactants on the left of the equation and products on the right. If you count the atoms in the reactants, there are
4 carbon atoms, 4 hydrogen atoms, and 2 oxygen atoms
1 carbon atom, 4 hydrogen atoms, and 2 oxygen atoms
1 carbon atom, 4 hydrogen atoms, and 4 oxygen atoms
4 carbon atoms, 4 hydrogen atoms, and 4 oxygen atoms
Increasing the amount of reactants may increase the amount of
atoms
matter
molecules
products
What is a sign of a physical change?
odor produced
change in state of matter
light
temperature change
What is a sign of a chemical change?
change in state of matter
change in size
change in shape
temperature change
Using the image, list the coefficients for the reaction.
2,2,3
1,2,2
4,3,2
4,2,1
Using the image above determine if a physical or chemical change has occurred in Model B.
A chemical change has occurred in model B. In the second cup you can see that the molecules have just rearranged.
A chemical change has occurred in model B. In the second cup you can see a bond (black line) has formed between the green and blue molecule and new light pink/light blue molecules have also formed.
A physical change has occurred in model B. In the second cup you can see that the molecules have just rearranged.
A physical change has occurred in model B. In the second cup you can see a bond (black line) has formed between the green and blue molecule and new light pink/light blue molecules have also formed.
Chemical Equation
A representation of a chemical reaction
the starting materials in a chemical reaction
the new substances that are formed in a chemical reaction
tells how many atoms, molecules, or formula units take part in a reaction
The Law of Conservation of Matter
tells how many atoms of an element are contained in one molecule or formula unit.
the starting materials in a chemical reaction
the new substances that are formed in a chemical reaction
A law stating that atoms are not created or destroyed during a chemical reaction.
Is the equation balanced?: 2H2O + O2 --> 4MgO + 3Fe
yes
no
Balance this equation
_Al +_HCl --> _H2 +_AlCl3
2,6,3,2
it's already balanced
4,12,3,4
2,1,4,5
The coefficient in 3H2O is
6
5
2
3
The small numbers in a chemical formula:
(the BLUE numbers)
Subscripts
Coefficients
Numbers
Molecules
The big/regular sized numbers in a chemical formula:
(the RED numbers)
Subscripts
Coefficients
Numbers
Molecules
How many Hydrogen are in H2O?
1
2
3
Not enough information.
How many Chlorine in 5NaCl?
1
5
3
Not enough information.
How many Oxygen in 3CO2?
3
2
6
Not enough information.
Is this equation balanced?
Yes, everything appears the same amount on each side.
No, there are too many oxygen on the left side.
Is this equation balanced?
Yes, everything appears the same amount on each side.
No, there are too many hydrogen on the left side.
No, there are too many oxygen on the left side.
