Understanding Standards materials are regularly reviewed to ensure they remain up to date. CPD Events Chemistry events These events will focus on the revised course assessment for session onwards. Delegates will take part in workshops, where they will have the opportunity to review and discuss the revised course documents with colleagues.
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Its solid-fuel rocket motor was prepared from nitrocellulose. He reached for the nearest cloth, a cotton apron, and wiped it up. He hung the apron on the stove door to dry, and as soon as it was dry, a flash occurred as the apron ignited.
His preparation method was the first to be widely imitated—one part of fine cotton wool Chemistry past paper be immersed in 15 parts of an equal blend of sulfuric and nitric acids. After two minutes, the cotton was removed and washed in cold water to set the esterification level and remove all acid residue.
By coincidence, a third chemist, the Brunswick professor F. Play media Deflagration test of nitrocellulose in slow motion. While guncotton is dangerous to store, the hazards it presents can be reduced by storing it dampened with various liquids, such as alcohol.
For this reason, accounts of guncotton usage dating from the early 20th century refer to "wet guncotton". The power of guncotton made it suitable for blasting. As a projectile driver, it had around six times the gas generation of an equal volume of black powder and produced less smoke and less heating.
However, the manufacturing process was not properly understood and few safety measures were put in place.
A serious explosion in July of that year killed almost two dozen workers, resulting in the immediate closure of the plant. Guncotton manufacture ceased for over 15 years until a safer procedure could be developed.
Unwashed nitrocellulose sometimes called pyrocellulose may spontaneously ignite and explode at room temperatureas the evaporation of water results in the concentration of unreacted acid. The washing and drying times of the nitrocellulose were both extended to 48 hours and repeated eight times over.
The acid mixture was changed to two parts sulfuric acid to one part nitric. Nitration can be controlled by adjusting acid concentrations and reaction temperature.
Soluble nitrocellulose, or a solution thereof, is sometimes called collodion. More-stable and slower-burning collodion mixtures were eventually prepared using less-concentrated acids at lower temperatures for smokeless powder in firearms. The first practical smokeless powder made from nitrocellulose, for firearms and artillery ammunition, was invented by French chemist Paul Vieille in Jules Verne viewed the development of guncotton with optimism.
He referred to the substance several times in his novels. His adventurers carried firearms employing this substance. The most noteworthy reference is in his From the Earth to the Moonin which guncotton was used to launch a projectile into space.Past papers and marking instructions.
Past Papers for chemistry 20 papers found for chemistry, displaying all papers. Page 1. The information in a past paper may be reproduced in support of SQA qualifications only on a non-commercial basis. If it is reproduced, SQA . I've checked environmental chemistry for questions relating to B6 syllabus points, but a search through all papers in the last 15 years suggests these syllabus points have yet to be examined by the IBO, which means they might be keen to introduce questions this year so students and teachers can get a feel for what their intentions are.
You can find all CIE Chemistry IGCSE () Paper 6 past papers and mark schemes below: June MS - Paper 6 CIE Chemistry IGCSE; June QP - Paper 6 CIE Chemistry IGCSE. AQA A-Level Chemistry Past Papers We have put together a comprehensive list of past papers for all of the AQA A-Level Chemistry exams.
Use these to practice your exam question answers and highlight revision topics you need to work on. Chemistry, Biology, Physics and Combined Mathematics model papers for GCE Advanced Level by University Lecturers, Professors. C12,C34 major updates click here · © IGCSE Past Papers · Powered by · Designed with the Customizr theme · IGCSE Past Papers · Powered by · Designed.