SES 141 Module 2 Assignment/Labs

A computer in a house uses 0.3 kilowatt for 15.6 hour. If electricity costs $0.4 per kilowatt-hour, how much does it cost (in dollars, to the penny) to use the computer? Use exact numbers; do not estimate.

1.87

A refrigerator in a house uses 0.5 kilowatt for 6.6 hour. If electricity costs $0.13 per kilowatt-hour, how much does it cost (in dollars, to the penny) to use the refrigerator? Use exact numbers; do not estimate.

0.43

Estimate energy (in joule) of one human heartbeat.

1

Estimate of the energy (in joule) contained in a quart of soda.

1,536,000

A 15.6 kilogram shotput is held 1.2 meters above the ground. What is the gravitational potential energy of the shotput relative to the ground? Use exact numbers; do not estimate.

183.456

Estimate your kinetic energy (in joule) when running at your top speed.

196

What is the approximate energy density (in MJ/kg) of crude oil?

44

What is the energy density (energy per mass) of butter and similar foods?

45 MJ/kg

What is the energy density (energy per mass) of gasoline?

45 MJ/kg

What is the approximate energy density (in MJ/kg) of natural gas?

55

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.

Match the quantity on the left with the beset answer on the right.

chemical element: different number of protons isotope: different number of nuetrons molecule: two or more atoms ionization: electron freed from an atom

Chemical reactions which absorb energy as they proceed are called ___________.

endothermic

Combining hydrogen and oxygen to make water

releases a lot of energy

what are the roles of a catalyst in the energentics of a chemical reaction

a catalyst increases the rate of reaction

In the presence of a net force, an object with a mass experiences an _______________ .

acceleration

A catalyst increases the rate of reaction but is not consumed by the reaction. Catalysts lower the ____________ energy.

activation

activation energy of a chemical reaction is the

energy input needed to get the atoms to start sharing their electrons

Match the quantity with their unit.

energy: joule speed: meter per second acceleration: meters per second per second power: watt

A mass is a fixed quantity of matter. The weight that mass feels depends on the __________ acting on the mass.

force

what happens energetically when chemical bonds are formed

forming bonds releases energy

Atoms in column 4 of the Periodic Table can be thought of as either possessing extra electrons or lacking electrons.

four or four

Which of the following elements are in the noble gas column of the periodic table of the elements?

helium, krypton

A substance that reduces the rate of a reaction is called an ___________ .

inhibitor

Every element produces a unique set of _________ lines so we can determine the composition of an object by identifying these lines.

spectral

A distance divided by a time is called a ____________.

speed