Experiment
|
Volume of Hydrochloric Acid (cm3)
|
Volume of Na2S2O3 (cm3)
|
Volume of H2O (cm3)
|
Time (s)
|
(s-1)
|
Concentration of Na2S2O3 (mol/dm3)
|
1
|
20
|
20
|
0
|
325
|
0.003
|
0.316
|
2
|
20
|
16
|
4
|
415
|
0.002
|
0.395
|
3
|
20
|
12
|
8
|
602
|
0.001
|
0.526
|
4
|
20
|
8
|
12
|
860
|
0.0011
|
0.79
|
5
|
20
|
4
|
16
|
1860
|
5.376
|
1.58
|
Calculations:
If the mass concentration of Na2S2O3 g/dm3 then determine the molar concentration for each volume of acid used in the experiment.
Number of Moles = =1/158g=0.00632mol
Na2S2O3= 23*2+32*2+16*3=
46+64+48= 158g
Molar Concentration = =
0.00632*1000/20=0.316
0.00632*1000/16=0.395
0.00632*1000/12=0.526
0.00632*1000/8=0.79
0.00632*1000/4=1.58
Analysis of Data: Why did you make up the solution to 20 cm3 each time?
Name TWO factors which were kept constant in the experiments.
The volume of hydrochloric acid was kept constant and the number of times it was repeated.
One of your graphs should be a straight line. It was the thiosulphate in moldm-3 against time for the reaction
Which is it?
What does this straight line tell you? As the concentration of sedum thiosulphate increases, the valueof1/time increases.
B elair High School
Subject: CAPE Chemistry Unit 1
All You Need to Know!
Name: ___ Abbyhay Gayle_____________________
Lab Write-up Sheet
Date: _6__/_11__/___21 Lab No. 2
Title: Plan and Design
Problem Statement: Aunty Marva, Abigail’s mother, was watching an advertisement promoting a new brand of baking soda however she has reservation about this brand being better than her favourite brand. As a CAPE student, plan and design an experiment to determine which brand of baking soda is more effective
This the format that the lab should take:
Theory: sodium bicarbonate is a widely used compound with the formula NAHCO3. It is
also known as baking soda, bicarbonate of soda,cooking soda,and sodium hydrogen
carbonate. vinegar is a dilute solution of acetic acid,HC2 H3 O2,made by fermentation of
wine or some other solution containing ethanol. Baking soda reacts with acetic acid in
vinegar to produce carbon dioxide gas, water, and an aqueous solution of sodium acetate.
Hypothesis : The greater the concentration of sodium bicarbonate in the baking soda, the more effective it is, for smaller amount of baking soda is needed for the same purpose.
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