University:
Felician University
Course:
CHEM-001 | Basic Chemistry
Academic year:

2020
Views:

421

Pages:

10
Author:

CometConductor

VOLUME PER VOLUME PERCENT SOLUTIONS • A 5% (V/V) 2-PROPANOL SOLUTION HAS 5 PARTS OF 2-PROPANOL FOR 100 PARTS OF SOLUTION. • TO MAKE 100ML OF A 5% 2-PROPANOL SOLUTION, PIPET 5ML OF 100% 2-PROPANOL INTO A GRADUATED CYLINDER, THEN RAISE THE VOLUME TO 100ML. PRACTICE PROBLEMS: • DESCRIBE AND CALCULATE HOW YOU WOULD MAKE 250ML 0F A 70% ETHANOL (V/V) SOLUTION. 70 ml = __x___ 100ml 250 ml X= 175 ml of ethanol, btv in GC to 250 ml PERCENTAGES, RATIOS, AND PROPORTIONS • PERCENT SOLUTIONS CAN ALSO BE REFERRED TO BY A RATIO OR PROPORTION. • EXAMPLE: • A 1% SOLUTION HAS PROPORTIONALLY 1PART SOLUTE TO 100 PARTS OF SOLUTION. CAN BE STATED AS • 1:99 RATIO OF SOLUTE TO SOLVENT • 1 PART IN 100 • 1/100 DILUTING PERCENT SOLUTIONS • USE THE FORMULA: C1 = conc. of stock soln. C2 = desired conc. of final soln. C1V1 = C2V2 V1 = Volume of stock soln. V2 = Desired volume of final soln. • CAN BE USED TO DILUTE ANY SOLUTION FROM A MORE CONCENTRATED ONE. • MAKE SURE ALL UNITS OF MEASURE ARE THE SAME ON BOTH SIDES OF THE EQUATION!!!! PRACTICE PROBLEM • PREPARE 50ML OF A 70% ALCOHOL SOLUTION FROM A STOCK SOLUTION OF 95% ALCOHOL. • C2 = 70% ALCOHOL Transfer 37ml of 95% alcohol to a • V2 = 50 ML GC, and add • C1 = 95% ALCOHOL water until the 95% alcohol x V1 = 70% alcohol x 50 mlvolume reaches 50 ml. V1 = 37 ml of 95% alcohol HOMEWORK FOR TONIGHT: • COMPLETE LEFT SIDES OF NOTES • COMPLETE PERCENT SOLUTIONS PRACTICE PROBLEMS PREPARATION OF SOLUTIONS DAY 2 USING STOCK SOLUTIONS GIVEN IN TERMS OF “X” • SOMETIMES THE CONC. OF STOCK SOLUTIONS IS GIVEN IN TERMS OF “X.” • X = NUMBER OF TIMES MORE CONC. THE SOLUTION IS THAN THE NORMAL WORKING CONC. OF THE SOLUTION. • 10X SOLUTION = 10 TIMES MORE CONC. THAN THE WORKING SOLUTION. • PLACES YOU’LL SEE THIS: • 50X TAE (ELECTROPHORESIS BUFFER) – NORMAL IS 1X