Describe a chemical reaction in terms of moles of reactant or product The following three vids all address the mole. The mole is not a concept we actually assess you on, but is a vital concept for you to understand for the rest of the unit. Very customisable so change as you like. Updated copies with more complicated calculations appear in later units.
Its also a good idea to read the brief notes after the alphabetical list. Most of the tests describe use simple apparatus like test tubes, teat pipette, wire for flame test nichrome, platinum best but costly and standard chemical reagents accessible in most school or college laboratories.
Where possible balanced symbol equations are given for the reactions occurring in doing the test. Sometimes a precipitate ppt initially forms with a limited amount of a reagent, it may then dissolve in excess of reagent to give a clear solution.
Both observations will be crucial for a positive id. There are no tests specific to identify a compound e.
Not all the reactions are good definitive tests, but they may well be important reactions of cations or anions you need to know about. In the organic section, only the alkene test is in GCSE double award science, but some others might be found in a full single or coordinated triple award GCSE syllabus.
The methods described give no recipe details or risk assessment, just basically what is needed, what you see and what you can or cannot deduce. There is a web page covering the methods some safety aspects of " Preparing and collecting gases ".
Use the alphabetical list to find the test you need. This section just illustrates the use of hazard warning signs with common examples, and may NOT provide sufficient detail for specific experiments, concentrations, coursework write up etc. Most acidic and alkaline solutions unless very dilute, VERY small quantities of acidic gases like chlorine, sulfur dioxide, nitrogen dioxide, very dilute bleaches.
These may not be that corrosive BUT they are irritating e. Harmful - poisonous but not toxic: Any substance like concentrated acidic or alkaline solutions which will attack many materials and destroy living tissue too!
Also includes substances like bromine. Most organic solvents like hexane, propanone acetonepetrol and other hydrocarbon fuels are easily ignited, easily catch fire. Chlorine, sulfur dioxide, hydrogen cyanide can cause death if breathed in with sufficient quantity, absorbed through the skin or ingested by swallowing.
Salts of hydrogen cyanide e. Chemicals that can act as oxidising agents e. Many oxidising agents donate oxygen to materials that burn and can be dangerously reactive. Many can cause combustion if mixed with an oxidisable combustible material.
They may cause materials to burn more fiercely. Radioisotopes giving off dangerous ionising radiation Explosive: These are due to electronic changes in the atoms, the electrons are excited and then lose energy by emitting energy as photons of light.
The high temperature promotes electrons to higher energy levels and the electrons re-emit the energy as photons of light as they go back to their normal stable level.
These emitted frequencies can be recorded on a photographic plate, or these days, more likely onto a sensitive photocell like in a digital camera and displayed on a high resolution computer screen. Each emission line spectra is unique for each element and so offers a different pattern of lines i.
Note the double yellow line for sodium, hence the dominance of yellow in its flame colour. In fact the simple flame test colour observations for certain metal ions relies entirely on the observed amalgamation of these spectral lines.
This is an example of an instrumental chemical analysis called spectroscopy and is performed using an instrument called an optical spectrometer simple ones are called spectroscopes.
It is a fast and reliable method of chemical analysis and this type of optical spectroscopy has enabled scientists to discover new elements in the past and today identify elements in distant stars and galaxies. The alkali metals caesium cesium and rubidium were discovered by observation of their line spectrum and helium identified from spectral observation of our Sun.This site has many resources that are useful for students and teachers of Chemistry 12 in BC as well as any senior high school Grade 12 chemistry course Canada, the US, or anywhere else in the world.
The main objective of this experiment is to carry out qualitative analysis to identify metal cations in unknown solution 1. INTRODUCTION An unknown material can be determined by using simple chemical tests and separations which is called as inorganic qualitative analysis.
In this section there are documents and results about the reactions produced between metal ions (cations) in solution with various anions. The specific precipitates / colour changes observed are reported for every positve result.
21 different metals ions where tested against 32 different anions. UST Corrosion Investigation Date: 6/1/ Version: DRAFT Page 1 of 38 Investigation Of Corrosion-Influencing Factors In Underground Storage Tanks With Diesel Service. Ultrafiltration (UF) is one of the best options for both one-stage and as part of multi-stage water and wastewater purification.
This review summarises the known facts about the fouling processes and cleaning procedures and details of the most successful physical and chemical cleaning combinations. Qualitative analysis is used to identify and separate cations and anions in a sample substance.
Unlike quantitative analysis, which seeks to determine the quantity or amount of sample, qualitative analysis is a descriptive form of analysis. In an educational setting, the concentrations of the ions.