ses ch 1
What is energy?
Energy is the capacity to do work.
You are given 12 grams of an unknown substance. How you would accurately determine the precise composition of the unknown substance?
Excite a small portion of it and identify the spectral lines.
A 17.4 kilogram shotput is held 1.8 meters above the ground. What is the gravitational potential energy of the shotput relative to the ground? Use exact numbers; do not estimate.
306.94
Estimate the temperature change (in Kelvin) to go from room temperature to boiling.
80
Glow sticks are an example of what type of chemical reaction?
Exothermic
Molecule
two or more atoms
Estimate the volume of one gallon of water (in m3).
0.0038
Estimate the area (in meter2) of one mobile phone.
0.0102
Using your answers from above, how much does it cost (in dollars) to toast a slice of bread?
0.0119
Using your answer above, how much does the electric company charge (in dollars) for 1e6 joule of energy?
0.033
Estimate how much the electric company charges (in dollars) for 1 kilowatt-hour.
0.12
Estimate the average time spent picking one's nose in minutes per day.
0.5
Estimate the number of pennies it costs to bring a gallon of water to a boil.
1.32
What is the energy density (energy per mass) of gasoline ?
45 MJ/kg
What happens energetically when chemical bonds are formed?
Forming bonds releases energy.
How is mass related to weight?
Mass is is a fixed quantity of matter. Weight depends on the forces acting on a mass.
Work is
a force times a distance the transfer of energy.
Ionization
electron freed from atom
Energy
joule
Power
watt
Estimate the fraction (a number between 0 and 1) of Earth's surface covered by water.
0.7
Estimate the width (in meter) of our giant mobile phone. Use the provided hint.
1,062.92
Estimate the power usage (in watt) of a typical toaster.
1,200
Estimate the volume of Earth's oceans in km3.
1,200,000,000
Estimate the depth of Earth's oceans in km.
11
Estimate the time it takes (in seconds) to toast a slice of bread.
120
Estimate the height (in meter) of our giant mobile phone. Use the provided hint.
2,152.413
Estimate the number of mobile devices in the USA.
2,400,000,000
using your answers above, estimate the area (in meter2) of all mobile phones in the USA.
2,448,000
From your answers above, how much energy (in joule) does it take to toast a slice of bread?
360,000
Estimate the mass (in kg) of 1 gallon of water.
4
Estimate the specific heat of water (in Joule/kilogram/Kelvin),
4,000
Estimate the energy (in Joule) to bring 1 gallon of water to a boil.
400,000
Estimate the number of people in the world.
7,000,000,000
Estimate the number of people currently picking their nose right now.
70,000,000
A 84 Watt light bulb is turned on for 1 minute. How much energy, in Joule, is used? Use exact numbers; do not estimate.
84 x 60 sec= 5,040
Estimate the number of gallons in Earth's oceans (in units of 1e20 gallons).
?/
What are the roles of a catalyst in the energetics of a chemical reaction?
A catalyst increases the rate of reaction. A catalyst is not consumed by the reaction.
Work, in the technical sense of the word, has units of
Joules
Select items that are forms of energy (in joule)
Kinetic Potential Gravitational
A vector has these properties
Magnitude Direction
Chemical Element
diff number of protons
A force is
is responsible for a change in motion. is a mass times an acceleration.
Speed
meter per second
Combining hydrogen and oxygen to make water
releases a lot of energy.
Make an order of magnitude estimate of the energy (in joule) contained in a quart of soda.
1,600,000
What are our 8 guidelines for making an order of magnitude estimate?
Guess Talk to your gut Divide and conquer Lie skillfully Punt Use guerrilla warfare Lower your standards Cross-check
Which of the following elements is in the noble gas column of the periodic table of the elements?
Hydrogen Helium XX Lithium Nitrogen Carbon Krypton XX
A 18 kilogram eagle is flying at 16 meters/sec. What is the kinetic energy (in joule) of the eagle? Use exact numbers; do not estimate.
ke= 1/2 mv^2. 2,304
Acceleration
meter per second per se cond
Estimate the number of strips of cooked bacon is the energy equivalent of 1 gallon of gasoline.
1,000
One human heartbeat uses about how much energy?
I Joule
Estimate the energy (in J) of one strip of cooked bacon.
100,000
Estimate the energy in one gallon of gasoline (in J).
100,000,000
Estimate the cost of electricity (in cents/kilowatt-hour).
12
Estimate the population of the USA.
300,000,000
Estimate the surface area of Earth in km2.
432,000,000
What is the energy density (energy per mass) of butter ?
45 MJ/kg
Isotope
different number of neutrons
A force is in the
direction of the change in motion.
The activation energy of a chemical reaction is the
energy input needed to get the atoms to start sharing their electrons.