Paper Chromatography of Aspirin
Category: Combined Chemistry
Speed of Reaction with Acids
The action of heat on metals and metal carbonates
Based on the data given, suggest which 2 were the metals and which 2 were the metal carbonates. Explain your answers.
Metals: A and D
Metal carbonates: B and C
Explanation:
Metals, when heated, will be oxidized by oxygen in the air to form metal oxides. The oxygen gained to form the oxide will cause the mass of the product formed to be higher. Mass increase for solids A and D after heating, so these two are metals.
Metal carbonates, when heated, can decompose to form metal oxides and carbon dioxide. The carbon dioxide formed escape to the surroundings, causing the mass of the solid product formed to be smaller.
The mass of B decreased after heating, so it must be one of the metal carbonates.
The mass and appearance of C remained unchanged, so it must be the other metal carbonate, which is not decomposed by the heat.
Explain how combustion engines produce nitrogen oxides.
Fuels are combusted in internal combustion engines, producing a lot of heat.
The high temperature condition causes oxygen and nitrogen in the air to react to form oxides of nitrogen.
What are the applications of esters?
Esters are used:
– in the manufacture of perfumes
– in the manufacture of artificial food flavorings
– as solvents for cosmetics and glues
– in the manufacture of soaps
Why must the temperature be kept at 37 deg C during fermentation of glucose solution?
At 37 deg C, the enzymes in yeast are the most active, so fermentation process will be fastest.
At low temperatures, the enzymes in yeast are inactive, so fermentation will be slow.
At high temperatures, the enzymes in yeast will be denatured, so fermentation will stop.
What is an addition reaction?
An addition reaction is a reaction in which new atoms are added to the organic compound by converting carbon-carbon double covalent bonds to carbon-carbon single covalent bonds.
What is a homologous series?
A homologous series is a family of organic compounds with:
– same functional group
– same general formula
– similar chemical properties
– gradual change in physical properties
Examples of homologous series:
– Alkanes
– Alkenes
– Alcohols
In paper chromatography, the start line is drawn with a pencil rather than a pen. Explain the reason for this.
Pen ink consists of a mixture of dyes that can dissolve in the solvent and contaminate the chromatogram.
Pencil lead is usually made of insoluble graphite, which made it suitable for drawing the start line in paper chromatography.
Describe the test for sulfur dioxide gas.
Bubble the gas into acidified potassium manganate (VII) solution.
KMnO4 solution changes color from purple to colorless in the presence of sulfur dioxide gas.