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WorksheetsCombustion reactions
Total questions: 45
Worksheet time: 39mins
The total heat output from a combustion reaction is called
Potential Energy
Kinetic Energy
Chemical Potential Energy
Enthalpy
Matter that has a definite shape and volume.
solid
liquid
gas
plasma
Matter that has a definite volume but no definite shape.
solid
liquid
gas
Matter that has no definite shape and no definite volume.
solid
liquid
gas
A measure of how much matter there is in an object?
mass
meter
density
volume
Anything that takes up space and has mass?
solid
liquid
gas
matter
The process by which liquid water turns into a gas?
Boiling Point
Melting Point
Evaporation
Absolute Zero
What is the process of measuring thermal energy from a sample , eg. food ?
Geometry
Thermodynamics
Calorimetry
exothermic
What system does not allow for transfer of either material or energy ?
Open
Closed
Isolated
A system of equations
Identify the TRUE statements about an exothermic chemical reaction.
Heat enters the system
absorbs heat
Has negative enthalpy
Has positive temp. change
Which substance has higher boiling point?
One with stronger intermolecular forces
One with weaker intermolecular forces
How do hot packs work?
By the reaction of a salt with water, that releases heat
By the reaction of a salt with water, that absorbs heat
What is a calorie?
Amount of carbohydrate in food
Amount of protein in food
The unit of energy in food
The mass of a substance
What is matter?
Substances that have mass
Substances that have volume
Things all around us
All of the above
In an endothermic reaction the energy level of products are lower than the reactants
True
False
Instrument that records the energy content of a sample is
a calorimeter
a thermometer
a spectrometer
a kilometer
Fuels in combustion may be
hydrocarbons, such as fossil fuel
magnesium
food
All of the above
Energy conversion in combustion is
From chemical potential energy to kinetic energy or thermal energy
mass to energy
potential to nuclear
thermal to electrical
An example of a closed system is
a saucepan with a lid
an insulated flask
a coffee cup with coffee
a water bottle with its cap closed
Why do we use styrofoam in a coffee cup calorimeter
For insulation
To keep heat inside and to not let heat come in
To create a closed system
To create an open system
The unit of enthalpy are _________ and ___________
Kilograms and grams
Celsius and farenheit
Calories and Joules
meters and centimeters
How many total Hydrogen molecules are present?
3
2
4
1
What is evaporation?
Solid to liquid transformation
liquid to gas transformation
gas to liquid transformation
Why do processes like melting, boiling and evaporation absorb energy?
Because they are endothermic
To overcome intermolecular forces
Because they need to break bonds
What is the unit of temperature ?
Celsius
Gram
Meter
Calorie
For an endothermic reaction
Enthalpy decreases
Surrounding temperature increases
Energy is absorbed
Energy is released
What is the boundary?
A separation between the system and the surrounding
A division between system and surrounding
How can you identify combustion?
Presence of Oxygen in reactant
Carbon dioxide and water in product
A negative enthalpy change
All of the above
What are elements?
Simplest building blocks of matter
That make up atoms and molecules
Two or more of which create compounds
All of the above
Which version of a calorimeter is more effective?
With one styrofoam cup
With two styrofoam cups
What is used to combust a sample in a calorimeter?
electrodes
fire
a match
a candle
What happens to a combustion reaction once the heat source is removed after being applied?
The heat of reaction will keep it going
The reaction will stop once all the fuel is used up
The reaction will be limited by oxygen
All of the above
Mixtures are chemical compounds
True
False
The toasting of bread is a__________ change
physical
chemical
When oxygen runs out before all the fuel is burned the combustion is ___________.
complete
incoplete
