Year 8 Reaction revision

Year 8 Reaction revision
Rearranging atoms
Balancing equations
Combustion
Thermal decomposition
Exothermic and endothermic 
Energy level diagrams
Bond energies.
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Year 8 Reaction revision
Rearranging atoms
Balancing equations
Combustion
Thermal decomposition
Exothermic and endothermic 
Energy level diagrams
Bond energies.

Slide 1 - Diapositive

What is the process of rearranging atoms in a substance called?
A
Molecular transformation
B
Chemical reaction
C
Atomic shuffling
D
Elemental reorganization

Slide 2 - Quiz

What is the term for the rearrangement of atoms within molecules?
A
Elemental modification
B
Molecular reorganization
C
Chemical rearrangement
D
Atomic shifting

Slide 3 - Quiz

What is the result of rearranging atoms in a chemical reaction?
A
Formation of new compounds
B
Molecule separation
C
Elemental fusion
D
Atom fusion

Slide 4 - Quiz

What is the term for breaking and reforming chemical bonds to rearrange atoms?
A
Elemental combination
B
Molecular synthesis
C
Chemical transformation
D
Atomic disassembly

Slide 5 - Quiz

What does not change during a chemical reaction
A
The products made
B
The total number of products
C
The total number of atoms each element
D
The total number of reactants.

Slide 6 - Quiz

What is the principle stating that matter cannot be created or destroyed?
A
Law of Motion
B
Principle of Displacement
C
Law of Conservation of Mass
D
Theory of Relativity

Slide 7 - Quiz

According to the law of conservation of mass, what happens to the total mass of a closed system?
A
It decreases
B
It increases
C
It fluctuates
D
It remains constant

Slide 8 - Quiz

What is the fundamental idea behind the law of conservation of mass?
A
Matter can transform into energy
B
Matter can defy gravity
C
Matter cannot vanish or come into being
D
Matter can change color

Slide 9 - Quiz

In a chemical reaction, what does the conservation of mass imply about the total mass of the reactants and products?
A
It doubles
B
It remains the same
C
It quadruples
D
It halves

Slide 10 - Quiz

What is a balanced symbol equation?
A
An equation without any numbers or symbols.
B
An equation with only one element represented.
C
An equation with unequal numbers of atoms on each side.
D
An equation where the number of atoms of each element is equal on both sides.

Slide 11 - Quiz

Why is it important to balance a symbol equation?
A
To confuse people who read the equation.
B
To make the equation look neat and tidy.
C
To satisfy the law of conservation of mass.
D
To increase the chemical reactivity of the substances.

Slide 12 - Quiz

What does the coefficient in a balanced symbol equation represent?
A
The volume of the substance.
B
The state of matter of a substance.
C
The atomic number of an element.
D
The number of molecules or atoms of a substance.

Slide 13 - Quiz

How can you balance a symbol equation?
A
By adding more reactants to one side of the equation.
B
By ignoring the need for balance.
C
By changing the chemical formula of the substances.
D
By adjusting the coefficients of the reactants and products.

Slide 14 - Quiz

What is the general equation for a combustion reaction?
A
2H2 + O2 → 2H2O
B
C + O2 → CO2
C
CH4 + 2O2 → CO2 + 2H2O
D
H2O → H2 + O2

Slide 15 - Quiz

Which of the following is not a product of a complete combustion reaction?
A
Water vapor
B
Sulfur dioxide
C
Carbon monoxide
D
Carbon dioxide

Slide 16 - Quiz

What is the primary requirement for a substance to undergo a combustion reaction?
A
High pressure
B
Absence of light
C
Presence of oxygen
D
Low temperature

Slide 17 - Quiz

Which type of reaction is a combustion reaction?
A
Decomposition
B
Exothermic
C
Synthesis
D
Endothermic

Slide 18 - Quiz

What is the role of a catalyst in a combustion reaction?
A
Speeds up the reaction
B
Forms new products
C
Increases the oxygen concentration
D
Reduces the temperature

Slide 19 - Quiz

What is thermal decomposition?
A
A process in which a substance combines with heat.
B
A process in which a substance breaks down due to heat.
C
A process in which a substance changes color due to heat.
D
A process in which a substance evaporates due to heat.

Slide 20 - Quiz

Which of the following is an example of thermal decomposition?
A
Formation of water from hydrogen and oxygen.
B
Decomposition of limestone to form quicklime and carbon dioxide.
C
Formation of rust on iron due to exposure to air.
D
Formation of salt from the reaction of an acid and a base.

Slide 21 - Quiz

What role does heat play in thermal decomposition?
A
Heat increases the stability of the compound.
B
Heat slows down the decomposition reaction.
C
Heat changes the chemical composition of the compound.
D
Heat provides the activation energy for the decomposition reaction.

Slide 22 - Quiz

Why is thermal decomposition important in industrial processes?
A
It increases the shelf life of perishable goods.
B
It allows the production of useful substances from raw materials.
C
It helps in the purification of water.
D
It reduces the environmental impact of manufacturing.

Slide 23 - Quiz

Which type of reaction absorbs heat from the surroundings?
A
Endergonic
B
Endothermic
C
Thermodynamic
D
Exothermic

Slide 24 - Quiz

In which type of reaction is heat released to the surroundings?
A
Exergonic
B
Endothermic
C
Thermodynamic
D
Exothermic

Slide 25 - Quiz

Which term describes a reaction that feels cold to the touch?
A
Exergonic
B
Exothermic
C
Endothermic
D
Endotherm

Slide 26 - Quiz

What type of reaction is photosynthesis considered to be?
A
Endergonic
B
Exothermic
C
Thermodynamic
D
Endothermic

Slide 27 - Quiz

In which type of reaction does the temperature of the surroundings increase?
A
Exergonic
B
Endothermic
C
Thermodynamic
D
Exothermic

Slide 28 - Quiz

What does an energy level diagram represent?
A
Distribution of energy levels for electrons
B
Atomic mass of an element
C
Number of electrons in an atom
D
Speed of light in a vacuum

Slide 29 - Quiz

What is the significance of the spacing between energy levels in a diagram?
A
Represents the number of protons in an atom
B
Shows the atomic radius of an element
C
Reflects the ionization energy of an element
D
Indicates the energy gap between levels

Slide 30 - Quiz

How does an electron transition from a lower to a higher energy level?
A
Releases energy as light
B
Undergoes nuclear fusion
C
Changes its spin orientation
D
Absorbs a specific amount of energy

Slide 31 - Quiz

What do downward arrows in an energy level diagram indicate?
A
Increase in atomic mass
B
Formation of a new element
C
Conversion of matter into energy
D
Electron transitioning to a lower energy level

Slide 32 - Quiz

What does the term 'ground state' refer to in an energy level diagram?
A
Highest energy level occupied by an electron
B
Lowest energy level occupied by an electron
C
Total energy of an atom
D
Energy released during nuclear decay

Slide 33 - Quiz

What is bond energy?
A
The energy required to break a chemical bond
B
The energy of an ionic bond
C
The energy stored in a chemical bond
D
The energy released when a bond forms

Slide 34 - Quiz

Which factor affects bond energy?
A
The volume of the molecule
B
The type of bond and the atoms involved
C
The temperature of the surroundings
D
The color of the compound

Slide 35 - Quiz

What is the typical unit for bond energy?
A
Kilojoules per mole (kJ/mol)
B
Grams per liter (g/L)
C
Kelvin (K)
D
Meters per second (m/s)

Slide 36 - Quiz

How does bond length relate to bond energy?
A
Longer bond length, higher bond energy
B
Bond length has no effect on bond energy
C
Shorter bond length, higher bond energy
D
Bond energy is unrelated to bond length

Slide 37 - Quiz

What happens to bond energy in an exothermic reaction?
A
Bond energy is absorbed
B
Bond energy becomes unpredictable
C
Bond energy remains unchanged
D
Bond energy is released

Slide 38 - Quiz