- WELCOME TO THE SOLUTION CONCENTRATION VIDEO TUTORIAL.
THIS IS AN INTRODUCTION TO AN OVERVIEW
OF THE SOLUTION CONCENTRATIONS
THAT ARE COMMONLY USED BY ALLIED HEALTH STUDENTS
AND CHEM 309 AND 305, 306.
SO LET'S START WITH WHAT THE DEFINITION IS.
A SOLUTION CONCENTRATION IS A QUANTITATIVE MEASURE
OF THE AMOUNT OF SOLUTE
DISSOLVED IN A GIVEN QUANTITY OF SOLUTION.
SO THERE ARE A TON OF DIFFERENT TYPES
OF CONCENTRATION UNITS OUT THERE.
AND SO AS I MENTIONED IN THE INTRODUCTION,
WE'RE GOING TO FOCUS ON THE FORMING TYPES
THAT ALLIED HEALTH STUDENTS WILL ENCOUNTER.
THE FIRST TYPE IS VERY STRAIGHTFORWARD.
IT'S THE MASS OF THE SOLUTE OVER THE VOLUME OF SOLUTION.
SO THIS WILL BE MASS OF SOLUTE
OVER VOLUME OF SOLUTION. OKAY.
NOW, MASS IS THE MOST CORRECT TERM, MASS OVER VOLUME
BUT DON'T BE SURPRISED IF YOU SEE WEIGHT OVER VOLUME.
THEY MEAN THE SAME THING
AND IT JUST DEPENDS ON WHO'S WRITING IT.
THE SECOND COMMON SOLUTION CONCENTRATION IS PERCENT MASS
OVER VOLUME.
AND SO IT WILL ALWAYS BE THE GRAMS OF THE SOLUTE
AND THIS WILL BE DEFINED AS OVER THE MILLILITERS OF THE SOLUTION.
SO IT LOOKS VERY SIMILAR, RIGHT, TO THE ONE ABOVE.
BUT HERE, THE MASS AND THE VOLUME,
THERE'S NO RULES.
THIS COULD BE ANY MASS UNIT AND ANY VOLUME UNIT.
BUT WHEN WE SEE PERCENT MASS VOLUME,
IT'S ALWAYS GOING TO BE THE SOLUTE IN GRAMS
AND THE SOLUTION IN MILLILITERS.
AND THEN WE NEED TO ACKNOWLEDGE THIS PERCENT HERE.
SO THE PERCENT IS VERY LITERAL, THE PERCENT, RIGHT?
SO PERCENT MEANS PER 100, RIGHT?
THERE'S A HUNDRED CENTS IN A DOLLAR,
A HUNDRED YEARS IN A CENTURY.
SO THE DIFFERENCE BETWEEN MASS
OVER VOLUME AND PERCENT MASS OVER VOLUME IS THAT IT'S GRAMS
OF SOLUTE OVER 100 MILLILITERS OF SOLUTION.
SO THAT ALLOWS FOR THE PERCENT PART.
AND ONCE AGAIN, OFTEN, THIS HAS THE PARENTHESIS HERE,
PERCENT MASS OVER VOLUME
OR DEPENDING ON WHO'S WRITING THE CONCENTRATION,
THEY MAY USE W FOR WEIGHT.
SO YOU JUST WANT TO RECOGNIZE THIS AS BEING INTERCHANGEABLE.
THEN WE HAVE THE CONCENTRATION OF MOLES OVER VOLUME.
AND HERE WE'RE GOING TO USE MOLARITY.
AND SO MOLARITY IS REPRESENTED BY A UPPER CASE M.
SO ANYTIME WE SEE A UPPER CASE M,
THAT TELLS US MOLES OF SOLUTE PER ONE LITER OF SOLUTION.
SO THIS CONCENTRATION UNIT IS SIMILAR
TO PERCENT MASS OVER VOLUME.
IN THAT WE HAVE SPECIFIC UNITS FOR MEASURING THE SOLUTE
AND THEN A PREDETERMINED VOLUME FOR THE SOLUTION.
AND SO IT'S REALLY IMPORTANT
THAT EVERY TIME YOU SEE A UPPERCASE M,
YOU TRANSLATE IT INTO MOLES OF SOLUTE PER LITER OF SOLUTION.
AND THEN THE FOURTH TYPE
OF CONCENTRATION UNIT THAT'S COMMON IN ALLIED HEALTH
AND BIOLOGICAL CONTEXT IS EQUIVALENTS PER VOLUME.
AND SO EQUIVALENTS IS USUALLY A UPPERCASE EQ FOR EQUIVALENTS.
AND THEN IT COULD BE ANY VOLUME
BUT WE'LL JUST GO WITH LITERS OF SOLUTION.
OKAY. AND SO WHAT IS SPECIAL
ABOUT EQUIVALENTS IS EQUIVALENTS HAVE TO DO-- SO,
WHAT'S THE DEAL WITH EQUIVALENTS?
IT TELLS US ABOUT THE AMOUNT OF CHARGE PRESENT,
RIGHT, IN THE SOLUTION. OKAY.
SO EQUIVALENTS IS ONLY GOING TO BE USED WITH IONIC COMPOUNDS.
SO IT MAKES NO SENSE TO USE EQUIVALENTS
WHEN WE'RE TALKING ABOUT COVALENT COMPOUNDS
BECAUSE COVALENT COMPOUNDS ARE NEUTRAL.
SO EQUIVALENTS IS A SPECIAL TYPE OF SOLUTION CONCENTRATION
WHEN WE'RE CONCERNED ABOUT THE OVERALL CHARGE OF THE SOLUTION.
SO HERE IS AN OVERVIEW
OF THE DIFFERENT CONCENTRATION UNITS THAT I'VE JUST DESCRIBED.
SO HERE WE HAVE THE PERCENT MASS VOLUME OR WEIGHT VOLUME.
SO THERE'S THE DEFINITION.
AND SO IF WE LOOK AT THE PLASMA CONCENTRATION
OF SODIUM CHLORIDE,
IF WE USE THE CONCENTRATION UNITS OF PERCENT WEIGHT VOLUME,
WE WOULD DESCRIBE THAT CONCENTRATION
AS 0.60% WEIGHT VOLUME OR MASS VOLUME.
SO IT'S THE SAME SOLUTION
BUT IF WE CHANGE THE CONCENTRATION UNITS,
SO THIS WOULD JUST--
RIGHT HERE IS MILLIGRAMS AND DECILITERS,
SO THIS IS AN EXAMPLE OF MASS OVER VOLUME.
HERE, IT'S THE SAME SODIUM CHLORIDE
AND THE SAME SOLUTION BUT IF WE CHANGE THE CONCENTRATION UNITS,
NOW WE DESCRIBE IT AS A 600 MILLIGRAMS PER DECILITER.
FOR MOLARITY, RIGHT, THAT'S THE UPPER CASE M
WHICH IS MOLES OF SOLUTE PER LITER OF SOLUTION,
THAT SAME SODIUM CHLORIDE CONCENTRATION
IF WE DESCRIBE IT IN TERMS OF MOLARITY WOULD BE 0.103 MOLAR.
AND BECAUSE THIS IS AN IONIC COMPOUND,
WE COULD DO IT IN TERMS OF EQUIVALENTS.
AND EQUIVALENTS, WE CAN USE THE METRIC PREFIXES
LIKE MILLI SO HERE'S MILLIEQUIVALENTS
PER METER WHICH IS COMMON WITH BIOLOGICAL SOLUTIONS
BECAUSE THE CONCENTRATION LEVELS ARE VERY LOW.
AND SO HERE, WHEN WE'RE LOOKING AT SODIUM CHLORIDE,
WE RECOGNIZE THAT IT DISSOCIATES INTO ONE SODIUM ION
AND ONE CHLORIDE ION.
SO THE SODIUM IONS
WOULD CREATE A HUNDRED AND THREE MILLIEQUIVALENTS OF CHARGE
AND THE CHLORIDE IONS WOULD CONTRIBUTE A HUNDRED
AND THREE MILLIEQUIVALENTS PER LITER OF CHARGE.
NOW, HERE WE HAD AN IONIC COMPOUND.
IF WE GO TO UREA, UREA HAS THE FORM,
HERE'S THE CHEMICAL STRUCTURE FOR UREA.
AND UREA IS ALL NON-METALS, IT'S A COVALENT COMPOUND.
SO WE CAN DESCRIBE THE CONCENTRATION OF UREA
IN OUR BLOOD PLASMA USING THE PERCENT WEIGHT OVER VOLUME
OR MASS OVER VOLUME OR MOLARITY.
HOWEVER, WE'RE NOT GOING TO TALK ABOUT MILLIEQUIVALENTS
BECAUSE THERE'S NO CHARGE PRESENT.
AND THE THING I WANT TO MAKE SURE
THAT'S REALLY CLEAR HERE IS THESE VARIOUS--
THESE CONCENTRATIONS LOOK VERY DIFFERENT
BUT THEY'RE DESCRIBING THE SAME SOLUTION.
SO THAT'S WHY IT'S IMPORTANT FOR YOU TO BECOME VERY COMFORTABLE
WITH THESE CONCENTRATION UNITS
SO THAT YOU CAN CONVERT BETWEEN ONE
OR ANOTHER AND RECOGNIZE THAT THERE'S STILL--
EVEN THOUGH THEY LOOK VERY DIFFERENT,
THEY'RE DESCRIBING THE SAME SOLUTE CONCENTRATION
AND THE SAME SOLVENT.
SO THIS CONCLUDES OUR INTRODUCTION
TO SOLUTION CONCENTRATIONS.
AND NOW, THERE WILL BE SUBSEQUENT TUTORIALS
THAT WILL FOCUS ON EACH ONE OF THESE FOUR CONCENTRATIONS.
SO IF YOU NEED ADDITIONAL PRACTICE DOING CALCULATIONS
WITH ANY ONE OF THESE FOUR DIFFERENT TYPES
OF SOLUTION CONCENTRATIONS,
PLEASE REFER TO THIS--
THE ADDITIONAL VIDEO TUTORIALS.