Vocabulary
Chemical potential energy
A covered beaker boiling on a hot plate is this type of system
Closed system
Name the necessary features of a scientific model.
Matter cannot be created or destroyed, but you can do this with it
Rearrange it
Change its form
Transform it
Your friend is playing music on their radio. You insult their taste in music, and they throw the radio at you. Name a type of energy involved in this situation.
Sound energy
Kinetic energy
Negative energy (just kidding)
Kinetic energy
Heat energy
Thermal energy
What is the difference between heat and temperature?
Heat is a type of energy, and temperature is a measure of heat
Exothermic reactions feel hot. Where does the heat energy come from?
Chemical potential energy that was stored in the system
This is true when a chemical reaction is balanced.
The number of each type of atom is the same in the reactants and in the products
In a reaction, the products are made from these
The reactants
Name for the area where a reaction or energy transformation takes place. It is separated by a boundary.
The system
A piece of wood contains 50 Joules of chemical potential energy. After it has completely burned, this many Joules of energy will be released.
50 Joules
Endothermic reactions absorb energy, so why do they feel cold?
Heat energy is being taken away from the surroundings and stored as chemical potential energy, which does not feel hot.
MgO + F2 --> MgF2 + O2
Is this reaction balanced? Why or why not?
No, because there is one O in the reactants and two in the products.
You increase the temperature of a piece of metal. Does the kinetic energy of the metal atoms increase or decrease?
Increase
The amount of an original energy source (such as coal or wind) that is actually transformed into electricity or usable energy
Energy efficiency
Wood releases less energy per gram than charcoal. Which contains more potential energy?
Charcoal
The reactants contain 5 J of chemical potential. The reaction is exothermic. Will more or less than 5 J of chemical potential be leftover after the reaction has finished?
Less (if the reaction is exothermic, some of the chemical potential got released as heat)
Ca + HI --> CaI2 + H2
Describe how you could balance this reaction.
Ca + 2HI --> CaI2 + H2
This is something that can occur during a chemical reaction.
Change in state of matter (solid/liquid/gas)
Change in color
New substances created
Energy transformation (light/heat/sound/etc.)
How much energy is contained in a substance per unit mass
Energy density
You eat a sandwich. Give an example of an energy transformation that occurs.
Chemical (sandwich) --> heat (body temperature)
Chemical (sandwich) --> kinetic (body movement)
Chemical (sandwich) --> chemical (fat storage)
State the energy transformation sequence for using fossil fuels to generate electricity for a TV.
Chemical potential (fossil fuels) --> heat (burning) --> kinetic (steam turns a turbine) --> electrical (electricity) --> light & sound (TV)
CH4 + 2O2 --> CO2 + 2H2O
You are performing this reaction. You start with 2 grams of CH4 and 2 grams of O2. How many grams of products will you have when the reaction is finished?
4 grams (the mass of the products is equal to the mass of the reactants)
You put the same amount of heat into a piece of metal and a piece of wood. The metal's temperature increases much more than the wood's temperature. Which substance has a lower specific heat?
Metal