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.