What is the assignment about?
i have been asked to create an educational presentation and accompanying tutorial notes in support
of the charity "Educate Africa" that my school sponsors. The intended audience is sixth-form
students who attend a school in a small African town without any laboratory facilities for them to
conduct their own practical’s. By contrasting "primary and secondary" titrimetric standards and
analysing potential sources of error, i will create a presentation or video and accompanying tutorial
booklet that shows how to precisely determine an analyte's composition and concentration in a
matrix.
What investigation will I be doing
Practical 1: determine the copper content in brass.
Part 1: make the brass solution.
Part 2: make a series dilution of copper nitrate and then ran all samples through the colorimeter.
Practical 2: determine the iron content of an iron tablet.
Part 1: standardisation of potassium permanganate with sodium oxalate solution.
Part 2: determine the concentration of iron by titrating potassium permanganate solution against an
unknown conc of iron sulphate made from iron sulphate tablets and sulfuric acid.
Practical 3: determine the bicarbonate content of water.
Part1: standardise hydrochloric acid with sodium carbonate.
Part 2: dilute hydrochloric acid.
Part 3: titrate diluted HCl against bottled water using a pH meter to determine the bicarbonate
content of water.
, Investigation 1: Determine the copper content of brass.
Aim :
In order to determine the unknown proportion of copper within a known quantity of brass, this
practical must be completed. This experiment uses colorimetry to determine a sample's absorption.
The colorimeter measures the absorption of brass and nitric acid solution in my practical.
Background :
A metal alloy called brass is primarily made of copper and zinc. Depending on the application, it
might also contain minuscule amounts of other metals like nickel, lead, and tin. Brass has been used
for many years and is highly valued for its tenacity, adaptability, and distinctive golden appearance.
It is frequently used in the production of many different products, such as musical instruments,
plumbing fixtures, decorative items, and ammunition casings. Brass can be customized for particular
applications by changing the ratios of copper and zinc in the alloy, which affects its physical
properties. Additionally, brass is salt water and corrosion resistant. In this experiment, nitric acid and
brass are reacted.
Cu(s) + 4HNO3(aq) → Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)
Equipment:
A beaker, A colorimeter, a stopwatch, A stirring stick, Purified water, Brass fillings ,Nitric acid ,Water
bath, Measuring cylinder, 10 cm3 volumetric flask,10 ml graduated pipette, plastic pasteur pipettes,
Hot plate, Electronic balance 3dp
Healthy and safety
Lab coat to be worn with safety glasses
hazard warning and safety sign to be read before any work
Bags or coat must be kept under bench or completely out of the way
Spills or accident must be told to a teacher. Rinse skin instantly if any chemical touches
Broken glass must be cautiously place in the yellow glass bin provide
Don protective eyewear and gloves that can withstand chemicals.
Perform the brass and acid reaction inside the fume cupboard.
Chemicals
Brass pieces that weigh about 0. 3 grams. -- The hazard associated with brass is copper
toxicity, zinc toxicity, skin irritation, eye irritation and possible explosion. By following the
health and safety this risk can be minimised
5 mol dm-3 of nitric acid. --The hazard associated with nitric acid is corrosiveness to skin and
eye, inhalation hazard and highly reactive which could lead to toxic fumes being released. By
following the health and safety this risk could be minimised
50 cm3 of a 0.5 mol dm-3 Copper (II) nitrate solution. --The hazard associated with copper
(II) nitrate solution is irritation to the skin and eye, it is hazardous to inhale, it could lead to
