Font size
WorksheetsEndothermic vs. Exothermic Reactions + Bonds Breaking/Forming
Total questions: 49
Worksheet time: 27mins
Does breaking bonds require energy, release energy, or not involve energy at all?
requires energy to break
releases energy when broken
No energy involved
Burning leaves and burning a fuel provide a(n) _______ change.
endothermic
exothermic
physical
When new chemical bonds form, energy ____________.
is taken into the system.
is released from the system.
stays the same in the system.
Bonding is the holding of two particles together by a significant ________ force
repulsive
attractive
neutral
In a reaction old bonds _______ and new bonds _______.
form , break
break, form
stay, added
Is this equation endo- or exo-thermic?
PCl3 (s) + Cl2 (g) --> PCl5 (s) + energy
endothermic
exothermic
Is this equation endo- or exo-thermic?
2KNO3 (s) + energy --> 2KNO2 (s) + O2
endothermic
exothermic
Is this reaction endo- or exo-thermic?
NH4NO2 + energy --> N2 (g) + 2H2O (g)
endothermic
exothermic
In an endothermic reaction, heat is ...
taken in
given out
If a chemical reaction is EXOTHERMIC, the temperature of the surrounding would....
Stay the same
Increase
Decrease
In an endothermic reaction the reaction is releasing energy.
True
False
The illustration shows cell respiration. Is the overall reaction of cell respiration an Endothermic or an Exothermic reaction?
Endothermic
Exothermic
A student mixed two chemicals to allow them to react. The temperature before the reaction was 25 ° C. The temperature after the reaction was 18° C. Which of the following is true?
The temperature did not change.
It is an endothermic reaction
It is an exothermic reaction
Energy is released from the reaction into the surrounding.
Baking bread and cooking an egg require an input of heat. These would be examples of....?
Endothermic processes
Exothermic processess
None of these
Photosynthesis takes place inside of leaf cells. Sunlight is required. Is this an Exothermic or an Endothermic reaction?
Endothermic
Exothermic
True or False:
All chemical reactions involve the absorption AND releasing of energy.
True because it takes energy to break bonds but energy is released when bonds form
False because exothermic reactions only release energy
False because endothermic reactions only absorb energy
False because it always requires energy to break bonds.
True or False:
Endothermic reactions only involve energy being absorbed.
True because endothermic reactions result in the surroundings getting colder
False because energy is also released when the bonds in the products are formed
False because endothermic reactions only involve energy being released
False because no energy is absorbed or released during endothermic reactions
Combustion reactions are known to be exothermic reactions. Why?
SELECT ALL THAT APPLY.
They release energy to the surroundings
They absorb energy from the surroundings
The surroundings get very hot
The surroundings get very cold
What three things does combustion need?
Fuel, oxygen, water
Fuel, oxygen, heat
Heat, oxygen, fire
When burning a fire, if I remove Oxygen, then the fire will...
no longer burn
keep burning
EXPLODE
Exothermic reactions release heat into the surroundings, so you observe a...
temperature increase
temperature decrease
no temperature change
Endothermic reactions absorb heat into its atoms, so you observe a...
temperature increase
temperature decrease
no temperature change
Endo means within. Endothermic reactions
Release heat
Absorb heat
Absorb coldness
Exo means outside. Exothermic reactions
Release heat
Absorb heat
Absorb coldness
For combustion reactions, their reaction equation should look like...
Hydrocarbon fuel + oxygen ----> ___+____
(Select 2 that go in the blanks)
CO2
O2
H2O
CxHy
These are diagrams of
atoms
molecules/compounds
This image is an example of a(n)...
atom
molecule/compound
What is the BEST definition of a chemical reaction?
A change in matter that produces one or more NEW substances
When two things combine and EXPLODE.
A reaction takes place in a closed system in which the temperature drops and condensation forms on the outside of the system. This reaction can be described as–
A combustion reaction producing water
a reaction that absorbs energy from the surroundings
a reaction that releases energy to the surroundings
a spontaneous reaction
Which is NOT true about the law of conservation of energy?
Energy can not be destroyed
Energy can only be rearranged
Energy can be created
energy in = energy out
The molecules on the right side of the equation are known as?
Products
Reactants
Molecules
Atoms
The molecules on the left side of the equation are known as?
Products
Molecules
Reactants
Atoms
Atoms CAN be destroyed.
True
False
What are the two REACTANTS in a combustion reactions?
Methane and Carbon Dioxide
Fuel and Oxygen
Carbon Dioxide and Water
Fuel and Carbon Dioxide
What are the two PRODUCTS in a complete combustion reaction?
Carbon Dioxide and Water
Carbon Monoxide and Methane
Carbon and Water
Fuel and Oxygen
Which of the following is NOT a type of fuel for a combustion reaction?
Gasoline
Hydrogen
Carbon dioxide
Ethanol
Which of the following is NOT a type of fuel for a combustion reaction?
C8H18
H2
CO2
C2H6O
Which of the following correctly shows what happens during the chemical reaction between hydrogen gas and chlorine gas?
What is incorrect about how this chemical reaction is shown?
The products and reactant labels are switched
There is nothing incorrect about this reaction.
The energy transfer arrows should all be the opposite directions
What is incorrect about how this chemical reaction is shown?
The products and reactant labels are switched
There is nothing incorrect about this reaction.
The energy transfer arrows should all be the opposite directions
What is incorrect about how this chemical reaction is shown?
The products and reactant labels are switched
There is nothing incorrect about this reaction.
The energy transfer arrows should all be the opposite directions
What evidence from our physical models supports the idea that breaking chemical bonds requires energy to enter the system?
Select all that apply.
When metal marbles are attracted to magnets and move closer to them, their speed increases
When a marble is used to "hit" a metal marble that is attracted to a magnet, the metal marble slows down as it moves away
When a marble is used to "hit" a metal marble that is attracted to a magnet, sometimes the marble is not going fast enough to actually "break" the attraction (bond)
When bringing two bar magnets close together, they start to pull your hands together and combine with ease, releasing energy in the form of sound
What evidence from our physical models supports the idea that forming chemical bonds releases energy to the surroundings?
Select all that apply.
When metal marbles are attracted to magnets and move closer to them, their speed increases
When a marble is used to "hit" a metal marble that is attracted to a magnet, the metal marble slows down as it moves away
When a marble is used to "hit" a metal marble that is attracted to a magnet, sometimes the marble is not going fast enough to actually "break" the attraction (bond)
When bringing two bar magnets close together, they start to pull your hands together and combine with ease, releasing energy in the form of sound
The grey line in this speed graph is showing what happens to the speed of particles when bonds...
FORM
BREAK
The grey line in this speed graph is showing what happens to the speed of particles when bonds...
FORM
BREAK
