Exo- or Endo-?
Kinetic or potential?
Chemical bonds
Q = ?
Etc.
100
Is combustion exothermic or endothermic?
Exothermic
100
Kinetic energy is energy of __________ and potential energy is _________ energy.
motion stored
100
What is stored in chemical bonds?
energy
100
What is the formula for Q, or thermal energy?
Q = m c deltaT
100
Name top-burning fuels in our "Comparing Fuels" lab.
methane (bunsen burner) butane (camp stove)
200
Give an example of an endothermic process.
Answers will vary.
200
Is the energy that is stored in chemical bonds considered potential or kinetic energy?
Potential energy
200
Does breaking chemical bonds release energy or store energy?
Release energy
200
What does "thermal energy" mean, and what are the units we measure it in?
Thermal energy = heat. It is measured in JOULES.
200
What is "activation energy?"
The energy to start a reaction.
300
Is fossil formation exothermic or endothermic? Explain.
Fossil formation is endothermic. Plants take in energy from the sun, store it in chemical bonds, then over millions of years, buried plants may turn into coal or oil.
300
Which of the following demonstrate potential energy? A car at the top of a hill, a car rolling down the hill, gasoline in the car's tank, the battery in the car's engine.
All except the car rolling down the hill. A car rolling is demonstrating kinetic energy, or energy of movement.
300
Is breaking bonds exothermic or endothermic? AND is this considered a + or - energy change?
Exothermic +
300
During the candle burning lab, how did you calculate "m" in the equation m c delta T?
"m" was the mass of the water.
300
What are the reactants and the products in a hydrocarbon combustion equation? Include energy.
Reactants: fuel (hydrocarbon) and oxygen Products: water, carbon dioxide, energy
400
Draw an exothermic potential energy diagram on the board. Label the activation energy.
Teacher will check if it is correct.
400
Give an example in which the energy of the sun has actually ended up inside a molecule on earth.
Photosynthesis: plants convert sunlight to the energy in the bonds of chemicals. Fossil fuel formation: same as above, except those plants got buried for millions of years.
400
Name the five types of chemical reactions
Combustion, decomposition, synthesis, double replacement, single replacement
400
Calculate the thermal energy, or Q, for a flame that heats up 1 gram of water 10 degrees. Get the unit correct!
Calculate the thermal energy, or Q, for a flame that heats up 1 gram of water 10 degrees. Get the unit correct!
400
What are two things you kept CONSTANT in your comparing fuels lab?
Time, volume of water, distance from flame to bottom of can
500
During ONE chemical reaction, chemical bonds are broken and re-formed. Since the breaking of bonds takes energy and the formation of bonds releases energy, what determines if the OVERALL reaction is endothermic or exothermic?
Add up how much energy is taken in and how much energy is given off. If more energy is given off than taken in, the reaction is exothermic. If more energy is taken in than given off, the reaction is endothermic.
500
Draw a potential energy diagram for the digestion of a potato chip in your body.
When you digest a potato chip, you are releasing energy stored in the bonds of the potato (and the grease!!), so it is exothermic. A diagram showing the lowering of the energy should be drawn, since energy is given off.
500
When double replacement occurs, what sign of a chemical reaction usually accompanies it?
A precipitate
500
When the wax in your candle burned, it seemed to disappear. Since we know matter can't disappear, what happened to it? HINT: it didn't "evaporate."
The carbon and hydrogen in the wax combined with oxygen in the air to form carbon dioxide and water, which then went into the air.
500
Which will release more energy when you burn it: methane or butane? Explain.
Since butane has a lot more chemical bonds in it, it has stored a lot more energy. So, when you burn it, it will give off more energy.
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