- WELCOME TO THE VIDEO TUTORIAL
ON ENERGY AND ITS RELATIONSHIP TO STATES OF MATTER OR PHASES.
SO, LET'S BEGIN WITH THE DEFINITION OF ENERGY,
IT'S THE CAPACITY TO DO WORK.
IT'S ALSO IMPORTANT TO KNOW THAT ENERGY IS CONSERVED,
THAT MEANS THAT IT CAN NEITHER BE CREATED NOR DESTROYED.
SO, THE UNITS OF ENERGY ARE CALORIES
OR JOULES.
SO, AND--
IN WORKING WITH ENERGY,
NOTE THAT MORE WE DIG INTO THE SUBJECT,
IT WILL BE IMPORTANT TO RECOGNIZE THAT WHEN YOU SEE
A NUMERICAL VALUE WITH THESE UNITS,
YOU RECOGNIZE IT AS AN ENERGY VALUE.
NOW, ENERGY, YOU KNOW, IT DOES COME IN DIFFERENT FORMS.
SO, WHEN ENERGY--
WE CALL KINETIC ENERGY IS THE ENERGY OF MOVEMENT.
AND THEN, OTHER FORMS OF ENERGY
CAN BE DESCRIBED AS POTENTIAL ENERGY.
AND THIS IS OFTEN CALLED STORED ENERGY.
SO, FOR EXAMPLE,
IF I HOLD THIS PENCIL UP, AND THEN BY--
IT HAS STORED ENERGY INSIDE IT,
SO COULD YOU--
CAN YOU, LIKE, PUT IT ON ME FOR A SEC? OKAY.
SO, WE CAN SAY THAT THERE'S POTENTIAL ENERGY
IN THIS PEN BECAUSE OF ITS POSITION.
AND THEN, IF I LET GO, THE ENERGY IS CONSERVED.
THAT POTENTIAL ENERGY BECAME THE KINETIC ENERGY
OF THE MOVEMENT AS I DROPPED THE PEN.
ALL RIGHT.
SO, THERE'S SOME EXAMPLES OF WHAT'S GOING ON THERE.
NOW, IN CHEMISTRY,
THE STORED ENERGY WON'T BE LIKE THE PEN,
THE STORED COMES FROM THE--
IT'S ELECTROSTATIC.
THE POTENTIAL ENERGY
OF CHEMISTRY COMES FROM EITHER POSITIVE
OR NEGATIVE CHARGES OR PARTIAL POSITIVE
AND PARTIAL NEGATIVE CHARGES.
SO, IT'S A LITTLE DIFFERENT FROM THE PHYSICAL WORLD TO THE--
OF THE CHEMICAL WORLD FOR POTENTIAL ENERGY
AND EVERYTHING HAS MOVEMENT.
SO, REMEMBER WITH ELECTROSTATIC INTERACTIONS
THAT THIS IS DESCRIBING THE ATTRACTION OR REPULSION
BETWEEN CHARGED PARTICLES,
WHETHER THEY HAVE FULL CHARGES OR PARTIAL CHARGES.
SO, WHEN WE HAVE A POSITIVE CHARGE AND A NEGATIVE CHARGE,
THEY ARE ATTRACTED TO EACH OTHER.
BUT IF WE HAVE TWO POSITIVE CHARGES,
THEY ARE GOING TO REPEL,
RIGHT, OR IF WE HAD TWO NEGATIVES, RIGHT?
SO, OPPOSITES ATTRACT LIKES REPEL.
ALL RIGHTY.
SO, NOW, LET'S TAKE WHAT WE'VE TALKED ABOUT WITH ENERGY
AND CONNECT IT WITH THE STATES OF MATTER.
AND THE IDEAS OF THE INTERPLAY
BETWEEN KINETIC ENERGY AND POTENTIAL ENERGY.
SO, WHEN WE'RE LOOKING AT SOLIDS, RIGHT, SO,
WE'LL HAVE THE KINETIC ENERGY,
EVERY STATE OF MATTER HAS BOTH.
EVERY STATE OF MATTER HAS MOVEMENT
AND EVERY STATE OF MATTER HAS SOME POTENTIAL ENERGY.
SO, EVEN SOLIDS--
EVEN THOUGH THE SOLID LOOKS VERY STILL IF WE WERE TO LOOK INSIDE,
WE WOULD SEE THAT THE ATOMS AND MOLECULES
WOULD BE VIBRATING INSIDE OF THEIR SOLID STATE STRUCTURE.
SO, BUT WHEN WE LOOK AT SOLIDS THOUGH,
THEY SEEM PRETTY QUIET.
WE ARE NOT-- WE DON'T SEE SOLIDS JUMPING OFF
THE BENCH OR ANYTHING.
SO, WE CAN SAY
THAT THE POTENTIAL ENERGY IS STRONGER, RIGHT?
SO, IT'S GREATER THAN, STRONGER,
THE POTENTIAL ENERGY IS STRONGER THAN THE KINETIC ENERGY.
NOW, WITH GAS MOLECULES,
IT'S THE OTHER WAY AROUND, RIGHT?
WITH GAS MOLECULES,
IF THIS WASN'T A VIDEO AND WE WERE IN THE SAME ROOM TOGETHER,
IF I SPRITZ A LITTLE PERFUME IN ONE CORNER,
WITHIN A COUPLE OF MINUTES,
THOSE GAS MOLECULES WOULD HAVE MOVED THROUGH THE ENTIRE ROOM.
AND WE WOULD ALL SMELL THE PERFUME.
SO, WITH GAS MOLECULES,
THE KINETIC ENERGY IS MUCH GREATER OR STRONGER
THAN THE POTENTIAL ENERGY.
AND SO, SOLID STATE CHEMISTRY,
WE'RE NOT GOING TO DEAL A LOT WITH THAT,
GASES WILL LOOK A LITTLE BIT AT,
BUT IT'S REALLY LIQUIDS WHERE IT'S VERY INTERESTING.
AND THAT'S WHERE WE HAVE A BALANCE
BETWEEN THE KINETIC ENERGY AND THE POTENTIAL ENERGY.
SO, IF I COULD DEMONSTRATE, RIGHT, WITH SOLIDS,
EVERYTHING IS LINKED TOGETHER.
AND IT'S VIBRATING AT THE ATOMIC LEVEL,
RIGHT, SO, THE POTENTIAL ENERGY IS STRONGER.
WITH GASES,
THEY'RE REALLY BE BOPPING AND DOING THEIR OWN THING,
MORE KINETIC ENERGY AND JUST VERY LITTLE POTENTIAL ENERGY.
LIQUIDS ON THE OTHER HAND,
THE LIQUID MOLECULES ARE SLIP SLIDING OVER EACH OTHER.
SO, THERE'S MOVEMENT OF THE LIQUID,
BUT THEY'RE ALWAYS TOUCHING EACH OTHER.
SO, THAT THEY'RE IN CONSTANT CONTACT, ALL RIGHT?
SO, THAT'S HOW WE CAN LOOK AT THE INTERPLAY
OF KINETIC AND POTENTIAL ENERGY WITH THE STATES OF MATTER.
NOW, IN CONVERTING FROM ONE STATE TO THE OTHER,
HEAT IS EITHER GOING TO BE--
NEED TO BE ADDED OR REMOVED.
SO, HEAT IS A FORM OF ENERGY.
NOW, TEMPERATURE IS A MEASURE
OF THE HOTNESS OR COLDNESS OF AN OBJECT.
AND SOMETIMES IT CAN BE CONFUSING
TO DISTINGUISH BETWEEN HEAT AND TEMPERATURE.
BEFORE WE TAKE A CLASS LIKE THIS,
WE MAY THINK THEY'RE THE SAME,
BUT THEY'RE DIFFERENT.
SO, HERE'S AN EXAMPLE
TO HELP YOU RECOGNIZE THE DIFFERENCE BETWEEN THEM.
LET'S SAY THAT WE HAD BOILING WATER, RIGHT?
SO, WATER BOILS AT AROUND A HUNDRED DEGREE C, OKAY?
SO, LET SAY WE HAVE ONE DROP OF BOILING WATER.
AND WE HAVE ONE GALLON OF BOILING WATER, ALL RIGHT?
THEY HAVE THE SAME TEMPERATURE.
NOW, I THINK WE'VE ALL BEEN SPLATTERED BY A DROP
OF BOILING WATER.
IT HURTS BUT IT'S NOT A BIG DEAL, RIGHT?
JUST A LITTLE BIT
OF ENERGY WAS DEPOSITED WITH THAT DROP OF BOILING WATER.
BUT IMAGINE IF SOMEONE POURED A GALLON OF BOILING WATER
ON OUR HAND OR OUR ARM, RIGHT?
THEN THEY WOULD BE PUTTING A LOT MORE ENERGY,
A LOT MORE HEAT ONTO US.
AND WE WOULD BE BURNED, OKAY?
SO, BOILING WATER SAME TEMPERATURE BUT THE HEAT
OR THE ENERGY IS DEPENDING ON HOW MUCH BOILING WATER THERE IS.
SO, HOPEFULLY THAT WILL HELP YOU DISTINGUISH BETWEEN THOSE TERMS.
AND NOW, WE'LL LOOK AT THE CHANGES OF STATE.
THIS CAN SEEM PRETTY STRAIGHTFORWARD.
SO, CHANGES OF STATE, RIGHT?
THIS WOULD BE THE PHYSICAL, RIGHT, THE PHYSICAL STATES OF--
OR CALLED THE PHASES, ALL RIGHT?
SO, THESE TERMS THEY MIGHT SEEM KIND OF SILLY AND OBVIOUS.
BUT IT'S IMPORTANT THAT YOU'RE FAMILIAR
WITH THEM BECAUSE WHEN YOU'RE ANSWERING QUESTIONS
ON EXAMS OR QUIZZES,
YOU GOT TO KNOW WHAT IN THE WORLD,
THE QUESTION'S ASKING
AND THAT RELIES ON YOUR UNDERSTANDING OF THE VOCABULARY.
SO, WE CAN SEE HERE, RIGHT,
THAT WE HAVE INCREASING TEMPERATURE
ALONG OUR VERTICAL AXIS.
AND SO, AS WE INCREASE THE TEMPERATURE,
WE'RE GOING TO INCREASE THE KINETIC ENERGY.
SO, FOR EXAMPLE, IF WE LOOK AT--
WE'LL JUST USE WATER AS AN EXAMPLE, RIGHT?
SO, HERE'S OUR SOLID, OUR ICE CUBE.
AS WE RAISE THE TEMPERATURE, RIGHT, WE CAN TAKE--
AND WE CAN MELT--
WE CAN MELT THE ICE INTO A LIQUID.
SO, IF WE ADD HEAT, IF WE ADD KINETIC ENERGY WE MELT.
IF WE TAKE HEAT AWAY, FREEZING, OKAY?
SO, FREEZING AND MELTING ARE REALLY THE SAME THING.
IT JUST DEPENDS ON YOUR PERSPECTIVE.
IF WE CONTINUE ADDING HEAT, RIGHT,
THEN WHAT WILL HAPPEN, RIGHT?
THIS WILL BE EVAPORATION OR BOILING.
OKAY, LIQUID TO GAS.
AND THEN, RIGHT,
ANYONE THAT'S DRIVEN A CAR, RIGHT, ON A--
ON A RAINY DAY.
WE SEE THAT THE WATER VAPOR WILL CONDENSE AS LIQUID
ON THE INSIDE OF OUR WINDSHIELD.
SO, THAT'S CONDENSATION OR CONDENSING, OKAY.
SO, THESE TERMS, I THINK MOST OF US HAVE SOME EXPERIENCE WITH.
IT IS POSSIBLE FOR SOME STATES OF MATTER TO JUMP DIRECTLY
FROM THE SOLID STATE TO THE GASEOUS STATE.
SO, IF WE GO--
IF WE ADD ENERGY TO GO FROM SOLID TO GAS,
THAT'S DESCRIBED AS A SUBLIMING, SUBLIMATION.
AND THEN, IT IS POSSIBLE TO TAKE SOMETHING FROM THE GAS STATE.
AND WE CALL THAT DEPOSITION OR WE DEPOSIT IT.
SO, FOR EXAMPLE, SOME--
AN EXPENSIVE JEWELRY THAT HAS A THIN LAYER OF GOLD,
FREQUENTLY THE GOLD IS PUT INTO THE GASEOUS STATE, AND THEN,
DEPOSITED AS A THIN FILM ON THE SURFACE OF THE JEWELRY.
SO, THESE ARE SOME IMPORTANT TERMS RELATED TO THE CHANGES
IN THE STATE OF MATTER THAT WILL BE HELPFUL TO YOU.
AND THEN, WE'LL SUMMARIZE THIS ALL.
WE'LL PUT IT ALL TOGETHER WITH A HEATING CURVE.
SO, HEATING CURVES BRING ALL OF THESE TOGETHER INTO ONE DIAGRAM.
NOW, ALONG THE Y AXIS HERE, WE HAVE TEMPERATURE.
AND WE HAVE THE TEMPERATURE INCREASING AS WE GO UP.
AND THEN, ALONG THE X AXIS,
WE HAVE HOW MUCH HEAT WE'VE APPLIED, ALL RIGHT?
SO, LET'S BRING THIS ALL TOGETHER.
SO, LET'S SAY--
SO, WE'RE STARTING WITH A SOLID, ALL RIGHT?
AND THAT SOLID IS AT A VERY LOW TEMPERATURE.
SO, AS WE ADD HEAT, WE RAISE THE TEMPERATURE OF THE SOLID.
BUT THEN, WE GET TO THE POINT WHERE NOW THE SOLID WILL MELT.
SO, WE'RE INITIALLY,
WE'RE INCREASING THE TEMPERATURE OF THE SOLID.
BUT NOW, NOTICE HERE,
WE'RE GOING TO GO FROM SOLID TO LIQUID, RIGHT?
SO, NOTICE THEN THAT THE TEMPERATURE REMAINS THE SAME.
WE CONTINUE TO ADD HEAT
BUT THAT HEAT ENERGY IS GOING INTO DISRUPTING THE ATTRACTION,
RIGHT, BREAKING APART THAT POTENTIAL ENERGY HOLDING
THE SOLIDS TOGETHER TO CREATE THE LIQUID.
ONCE, THE ENTIRE SUBSTANCE HAS BECOME A LIQUID,
THEN AS WE CONTINUE ADDING HEAT,
WE ARE ONCE AGAIN RAISING THE TEMPERATURE.
UNTIL WE GET TO THE POINT, THE BOILING POINT OF THE LIQUID.
NOW, WE WILL CONTINUE ADDING HEAT
BUT ALL OF THAT ENERGY IS GOING
INTO CONVERTING THE LIQUID INTO A GAS,
SO HERE WE WERE MELTING.
AND HERE WE'RE BOILING.
AND THEN, ONCE
ALL OF THE MATERIAL HAS MADE IT INTO THE GAS PHASE,
THEN IF WE CONTINUE ADDING MORE HEAT,
WE WILL RAISE THE TEMPERATURE
OF THE GAS TO HIGHER AND HIGHER TEMPERATURES.
SO, IT'S IMPORTANT TO UNDERSTAND THAT AS WE ADD HEAT,
WE DON'T ALWAYS GET A TEMPERATURE INCREASE
THAT THAT ENERGY COULD GO INTO CREATING A PHASE CHANGE, RIGHT?
SO, AS WE INCREASE THE TEMPERATURE,
WE INCREASE THE KINETIC ENERGY.
SO, THE MELTING POINT, RIGHT,
SOLIDS MELT INTO LIQUIDS
WHEN THAT KINETIC ENERGY OVERCOMES THE POTENTIAL ENERGY
THAT'S HOLDING THOSE MOLECULES IN THE SOLID STATE.
THIS IS DESCRIBED AS THE HEAT OF FUSION.
THE BOILING POINT, RIGHT,
SO LIQUIDS BOIL INTO GASES WHEN THE KINETIC ENERGY ONCE AGAIN,
OVERCOMES THE POTENTIAL ENERGY
AND WE DESCRIBE THIS AS THE HEAT OF VAPORIZATION,
THE ENERGY TO TRANSFORM A LIQUID TO A GAS OR VICE VERSA.
AND SO, THEN JUST AS A--
AS A CLOSING COMMENT HERE,
THAT'S WHY STEAM BURNS ARE SO DAMAGING, ALL RIGHT?
BECAUSE THE WATER IN THE STEAMER BOTH AT A HUNDRED DEGREES,
RIGHT, BUT WHEN THE STEAM HITS OUR SKIN,
IT UNDERGOES A PHASE CHANGE
WHICH RELEASES ADDITIONAL HEAT TO OUR SKIN.
SO, LET'S LOOK BACK AT THE CHART ONE LAST TIME, RIGHT?
SO, IF THIS IS THE TEMPERATURE
OF THE STEAM AND IT HITS OUR SKIN,
RIGHT, WE GET THE INITIAL BURN FROM THE TEMPERATURE.
BUT THEN, THE STEAM, RIGHT, SO,
THE STEAM DUMPS ITS HEAT INTO US.
AND THEN, AS IT CONDENSES INTO A LIQUID,
IT'S GIVING OFF HEAT, RIGHT?
SO, HERE WE WERE PUTTING HEAT IN.
NOW, WHEN WE GO BACKWARDS, HEAT IS BEING RELEASED.
AND SO, THAT'S WHY IT'S ALL--
BE CAREFUL AROUND STEAM BECAUSE ITS--
IT BURNS AS TWICE.
ALL RIGHTY.
SO, THAT CONCLUDES OUR REVIEW OF ENERGY WITH--
AND IN TERMS OF KINETIC AND POTENTIAL ENERGY.
SO, PLEASE TAKE THE TIME NOW
TO WORK A COUPLE OF PRACTICE PROBLEMS,
SO THAT YOU CAN REINFORCE YOUR UNDERSTANDING.