Topics: Ethanol, Breathalyzer, Concentration Pages: 3 (769 words) Published: April 10, 2013
Chemistry lab on Alcohols
Cristina Tolosa
Jhony Arias

Data Collection:
Table One: absorbance recorded with the different substances Try oneTry two

SubstanceAbsorbanceSubstanceAbsorbance
4ml of water, 0 ml of ethanol0.00004ml of water, 0 ml of ethanol0.000 3ml of water, 1 ml of ethanol0.1253ml of water, 1 ml of ethanol 0.058 2 ml of water, 2ml of ethanol0.1472ml of water, 2ml of ethanol0.087 1ml of water, 3ml of ethanol0.1531ml of water, 3 ml of ethanol0.099 0 ml of water, 4ml of ethanol0.1750ml of water, 4ml of ethanol0.139 Mouthwash without alcohol0.178Mouthwash without alcohol0.503 Blue mouthwash0.180Blue mouthwash0.164

Average Absorbance
0.000
0.092
0.117
0.126
0.157
0.341
0.172

Observations from data collected: Overall through the range of data from 0.000 to 0.180 there was a small range most of the outcomes were the same and consistant, the only outlier of the data was the no alcohol mouthwash which ranged from 0.178 to o.503 showing that either during the lab there was a technical error made or it had a lot of alcohol concentration. Calculations made in lab:

Concentration of ethanol solution: 96%
Density: 0.78g/ml
m/m% = mass of solute * 100/ mass of solution
C1*V1 = C2V2
Convert from percentage to molarity
Find equation
Calibration curve find unkown values
Example of doing this:
Density of solution: mass of solution/volume of solution
Concentration of ethanol: mass of solute/mass of solution *100 Table two: concentrations; the molarities
substanceConcentration of try oneConcentration of try 2Averga concentration 4 ml of water, 0 ml of ethanol0.0000.0000.000
3ml of water, 1 ml of ethanol 0.8300.8300.830
2ml of water, 2ml of ethanol1.6501.6501.650
1ml of water 3ml of ethanol2.4802.4802.480
0ml of water, 4ml of ethanol3.3003.3003.300
Mouthwash without alcohol3.3003.3003.300
Blue mouthwash3.3003.3003.300

Graph #1 Comparing results of try one with try two:...