exam 2

Question 1

molar mass

Answer 1

mass of one mole of any atom or molecule in grams
molar mass of any element is the same as the atomic mass (different units)
g/mol

Question 2

HOW TO CALCULATE MOLAR MASS

Answer 2

use molar mass to convert between grams and moles
avogadros number = conversion factor between moles and number of particles
calculate mass percent of element in compound

Question 3

fuels are combusted to release energy from a potential form (chemical) to kinetic form (heat)

Question 4

kinetic vs potential

Answer 4

potential - found in potential bonds between molecules
kinetic - heat released (combustion)

Question 5

chemical vs heat energy

Answer 5

chemical - energy in bonds between atoms
heat - energy released when combustion happens

Question 6

where do organic fuels get their energy from

Answer 6

sun via photosynthesis

Question 7

how to calculate energy changes in a reaction

Answer 7

potential energy = positive value
kinetic energy = negative value

Question 8

convert between mass of fuel and energy of fuel

Answer 8

how energy content is measured
energy changes in a chemical reaction using bond energies
use energy changes in combustion reaction to determine heat of combustion or energy content of a fuel

Question 9

how does calorimeter work

Answer 9

measures energy released in a reaction

Question 10

equation for conversion efficiency

Answer 10

useful energy output/energy input (x100?)

Question 11

use conversion efficiency equation to determine the efficiency, the energy of coal, or electricity output given two factors
use different units of energy and be able to convert between them

Question 12

prefixes for number of carbons in a hydrocarbon

Answer 12

meth - 1
eth - 2
prop - 3
but - 4
pent - 5
hex - 6
hept - 7
oct - 8
non - 9
dec - 10

Question 13

name, draw structural formula, condensed structural formula for isomers of alkanes with four or more carbons

Question 14

biomass vs biofuels

Answer 14

biofuels are created from biomass
biomass is recently grown biological materials

Question 15

which molecules from plants are used to produce biofuels

Answer 15

ethanol and oil - sugars from corn and sugar cane
biodiesel comes from oil - cooking oil and animal fats

Question 16

key biological or chemical processes used to convert matter into biofuels

Answer 16

transesterification of methyl esters creates biodiesel, fermentation creates sugar

Question 17

chemical features of ethanol and biodiesel

Question 18

lifecycle of biodisel

Answer 18

oils brought to campus, transesterification to create biodiesel

Question 19

comparison between generating electricity via batteries vs turbine generators

Answer 19

batteries are potential energy, and generators are kinetic energy which is harder to transport and must be used quicker

Question 20

oxidation vs reduction

Answer 20

oil rig
connect formation of ionic compounds and redox reactions that form ions

Question 21

write half reactions

Answer 21

combine half reactions
balance materials and charge
cancel out electrons when combining half reactions into overall reactions

Question 22

what happens to the anode of a battery

Answer 22

oxidation and donation of electrons

Question 23

what happens to the cathode of a battery

Answer 23

reduction and recieved electrons

Question 24

how do batteries work

Answer 24

oxidize metals via spontaneous reactions and capture electricity conducted between the anode and cathode

Question 25

fuel cells

Answer 25

continuous input of fuel and outputs
release electrons from the input across a catalyst and absorb the electrons via the output

Question 26

photovoltaics

Answer 26

relies on photons to release/excite electrons and generate current of electricity

Question 27

n layer

Answer 27

layer with an excess of electrons

Question 28

p layer

Answer 28

layer with shortage of electrons

Question 29

semiconductor

Answer 29

materials with limited capacity of conducting an electric current

Question 30

DIFFERENT TYPES OF PV - pros and cons of technologies