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Litmus paper after being used. The main use of litmus is to test whether a solution is acidic or basic, as blue litmus paper turns red under acidic conditions, and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range 4.5–8.3 at 25 °C (77 °F). Neutral litmus paper is purple. [2]
The 1958-59 winner was an "all schools" winner; beginning with the 1959-60 academic year winners were held in all five classifications. The classifications were renumbered in 1980-81, with Class B becoming Class A and the other classes adding one letter (thus, Class A became Class AA, and so forth). [1]
Chemistry is the scientific study of the properties and behavior of matter. [1] It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances.
The chemical chameleon reaction shows the process in reverse, by reducing violet potassium permanganate first to green potassium manganate and eventually to brown manganese dioxide: [1] [2] [5] KMnO 4 (violet) → K 2 MnO 4 (green) → MnO 2 (brown/yellow suspension) Blue potassium hypomanganate may also form as an intermediate. [6]
Chemical energy is the energy of chemical substances that is released when the substances undergo a chemical reaction and transform into other substances. Some examples of storage media of chemical energy include batteries, [1] food, and gasoline (as well as oxygen gas, which is of high chemical energy due to its relatively weak double bond [2] and indispensable for chemical-energy release in ...
For HL, questions in section A (45 marks) consists of the core of the option, which may be common to the SL paper, and questions in section B (20 marks) are based on the extension of the option. Paper 3 (HL only: 30 raw marks contributing 20% of the course, 1 hour) consists of 4 compulsory questions based on the pre-seen case study annually ...