2Q03 W2023 1
Lab #3 – Acid Buffering Capacities of Water – Environmental Science 2Q03 W2023
DATE: _____________________ STUDENT NAME:
_______________________________________________________________
STUDENT #: ____________________ TA NAME: __________________________ LAB#: ___________
Introduction
Through acid-base titration, this laboratory activity evaluates the buffering or acid
neutralizing capability (ANC) of various water samples. The term "buffering capacity" describes
the power to withstand pH variations. The quantity of base, or substances in the water that can
take protons (H+), controls this ability and maintains a steady pH level. (E.g. carbonate).
Although the terms ANC and alkalinity are frequently used equally, in the literal sense ANC is
measured on unfiltered water samples (solutes + particulates) and alkalinity is measured on
purified water samples (solutes only).
Lab Overview:
By steadily adding 0.1 N H2SO4, you must lower the pH of your water sample to pH 4.5
before titrating very slowly between pH 4.5 and 3.5. These numbers are related to how carbon
behaves and the pH levels at which the main carbon species changes.
First, you must note the original pH of your water sample. Then, add acid until the pH
reaches 4.5, and note the TOTAL VOLUME of 0.1N H2SO4 that has been added up to this
point. Then, until you achieve a pH value of 3.5, cautiously add acid one drop at a time, noting
the amount of acid added (for example, 0.01 ml) and the pH value each time.
Your ultimate pH level should be between 4.5 and 3.5, and you should add ten to fifteen
volume units of acid.
, 2Q03 W2023 2
The Lab consist of two parts:
Part A: Acid Neutralizing Capacity of Known Water Sample
The specific lab objective is to determine the acid-neutralizing capacity of a known
(bottled) water sample. Three times this titration will be repeated using a burette with sulfuric
acid.
Results:
The results for the lab part A are tabulated as below:
Table 1: Acid Neutralizing Capacity of Known Water Sample (Bottled)
Titration 1 Titration 2 Titration 3
Starting pH 7.26 Starting pH 7.35 Starting pH 7.28
Normality of acid 0.1 Normality of acid 0.1 Normality of acid 0.1
Volume of sample Volume of sample Volume of sample
100 100 100
(mL) (mL) (mL)
Total volume of Total volume of Total volume of
acid added to reach 5.63 acid added to reach 5.54 acid added to reach 5.92
pH 4.5 (mL) pH 4.5 (mL) pH 4.5 (mL)
Individual Increments of acid Individual Increments of acid Individual Increments of acid
added below pH 4.5 (mL) added below pH 4.5 (mL) added below pH 4.5 (mL)
Volume added Volume added Volume added
pH pH pH
(mL) (mL) (mL)
, 2Q03 W2023 3
e.g.: 4.4 e.g.: 0.01 e.g.: 4.4 e.g.: 0.01 e.g.: 4.4 e.g.: 0.01
e.g.: 4.3 e.g.: 0.01 e.g.: 4.3 e.g.: 0.01 e.g.: 4.3 e.g.: 0.01
4.6 0 4.55 0 4.6 0
4.29 0.09 4.05 0.08 4.14 0.11
4.1 0.03 3.86 0.06 3.92 0.06
3.68 0.12 3.71 0.05 3.8 0.04
3.56 0.06 3.57 0.09 3.67 0.07
3.43 0.08 3.48 0.04 3.6 0.02
3.36 0.04 3.4 0.04 3.51 0.03
3.3 0.09 3.34 0.08 3.44 0.08
3.25 0.08 3.29 0.07 3.37 0.08
3.21 0.09 3.25 0.09 3.3 0.11
3.18 0.03 3.2 0.07 3.26 0.07
3.14 0.08 3.17 0.04 3.2 0.05
3.08 0.07 3.1 0.16 3.17 0.08
Part B: Acid Neutralizing Capacity of Unknown Water Sample (Sulfur Springs)
The specific lab goal is to measure the acid neutralizing capacity of an unidentified water
sample from the Hamilton region (be aware that the geological and mineral characteristics of the
area may have an impact on buffering capacity). Three times this titration will be repeated using
a burette with sulfuric acid.
Results:
The results for the Lab part B are tabulated as below:
Table 2: Acid Neutralizing Capacity of Unknown Water Sample (Sulfur Springs)
Titration 1 Titration 2 Titration 3
Starting pH 7.32 Starting pH 7.48 Starting pH 7.54
Normality of acid 0.1 Normality of acid 0.1 Normality of acid 0.1
Volume of sample Volume of sample Volume of sample
100 100 100
(mL) (mL) (mL)
Total volume of Total volume of Total volume of
acid added to reach 3.82 acid added to reach 3.32 acid added to reach 3.21
pH 4.5 (mL) pH 4.5 (mL) pH 4.5 (mL)
Individual Increments of acid Individual Increments of acid Individual Increments of acid
Lab #3 – Acid Buffering Capacities of Water – Environmental Science 2Q03 W2023
DATE: _____________________ STUDENT NAME:
_______________________________________________________________
STUDENT #: ____________________ TA NAME: __________________________ LAB#: ___________
Introduction
Through acid-base titration, this laboratory activity evaluates the buffering or acid
neutralizing capability (ANC) of various water samples. The term "buffering capacity" describes
the power to withstand pH variations. The quantity of base, or substances in the water that can
take protons (H+), controls this ability and maintains a steady pH level. (E.g. carbonate).
Although the terms ANC and alkalinity are frequently used equally, in the literal sense ANC is
measured on unfiltered water samples (solutes + particulates) and alkalinity is measured on
purified water samples (solutes only).
Lab Overview:
By steadily adding 0.1 N H2SO4, you must lower the pH of your water sample to pH 4.5
before titrating very slowly between pH 4.5 and 3.5. These numbers are related to how carbon
behaves and the pH levels at which the main carbon species changes.
First, you must note the original pH of your water sample. Then, add acid until the pH
reaches 4.5, and note the TOTAL VOLUME of 0.1N H2SO4 that has been added up to this
point. Then, until you achieve a pH value of 3.5, cautiously add acid one drop at a time, noting
the amount of acid added (for example, 0.01 ml) and the pH value each time.
Your ultimate pH level should be between 4.5 and 3.5, and you should add ten to fifteen
volume units of acid.
, 2Q03 W2023 2
The Lab consist of two parts:
Part A: Acid Neutralizing Capacity of Known Water Sample
The specific lab objective is to determine the acid-neutralizing capacity of a known
(bottled) water sample. Three times this titration will be repeated using a burette with sulfuric
acid.
Results:
The results for the lab part A are tabulated as below:
Table 1: Acid Neutralizing Capacity of Known Water Sample (Bottled)
Titration 1 Titration 2 Titration 3
Starting pH 7.26 Starting pH 7.35 Starting pH 7.28
Normality of acid 0.1 Normality of acid 0.1 Normality of acid 0.1
Volume of sample Volume of sample Volume of sample
100 100 100
(mL) (mL) (mL)
Total volume of Total volume of Total volume of
acid added to reach 5.63 acid added to reach 5.54 acid added to reach 5.92
pH 4.5 (mL) pH 4.5 (mL) pH 4.5 (mL)
Individual Increments of acid Individual Increments of acid Individual Increments of acid
added below pH 4.5 (mL) added below pH 4.5 (mL) added below pH 4.5 (mL)
Volume added Volume added Volume added
pH pH pH
(mL) (mL) (mL)
, 2Q03 W2023 3
e.g.: 4.4 e.g.: 0.01 e.g.: 4.4 e.g.: 0.01 e.g.: 4.4 e.g.: 0.01
e.g.: 4.3 e.g.: 0.01 e.g.: 4.3 e.g.: 0.01 e.g.: 4.3 e.g.: 0.01
4.6 0 4.55 0 4.6 0
4.29 0.09 4.05 0.08 4.14 0.11
4.1 0.03 3.86 0.06 3.92 0.06
3.68 0.12 3.71 0.05 3.8 0.04
3.56 0.06 3.57 0.09 3.67 0.07
3.43 0.08 3.48 0.04 3.6 0.02
3.36 0.04 3.4 0.04 3.51 0.03
3.3 0.09 3.34 0.08 3.44 0.08
3.25 0.08 3.29 0.07 3.37 0.08
3.21 0.09 3.25 0.09 3.3 0.11
3.18 0.03 3.2 0.07 3.26 0.07
3.14 0.08 3.17 0.04 3.2 0.05
3.08 0.07 3.1 0.16 3.17 0.08
Part B: Acid Neutralizing Capacity of Unknown Water Sample (Sulfur Springs)
The specific lab goal is to measure the acid neutralizing capacity of an unidentified water
sample from the Hamilton region (be aware that the geological and mineral characteristics of the
area may have an impact on buffering capacity). Three times this titration will be repeated using
a burette with sulfuric acid.
Results:
The results for the Lab part B are tabulated as below:
Table 2: Acid Neutralizing Capacity of Unknown Water Sample (Sulfur Springs)
Titration 1 Titration 2 Titration 3
Starting pH 7.32 Starting pH 7.48 Starting pH 7.54
Normality of acid 0.1 Normality of acid 0.1 Normality of acid 0.1
Volume of sample Volume of sample Volume of sample
100 100 100
(mL) (mL) (mL)
Total volume of Total volume of Total volume of
acid added to reach 3.82 acid added to reach 3.32 acid added to reach 3.21
pH 4.5 (mL) pH 4.5 (mL) pH 4.5 (mL)
Individual Increments of acid Individual Increments of acid Individual Increments of acid
