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For example, the chemical formula for glucose is C 6 H 12 O 6 (meaning that it is a molecule with 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms). The chemical formula of the water molecule, H 2 O, indicates that it contains two hydrogen atoms and one oxygen atom. A subscript is also used to distinguish between different versions of a ...
The numbers 200-900 would be confused easily with 22 to 29 if they were used in chemistry. khīlioi = 1000, diskhīlioi = 2000, triskhīlioi = 3000, etc. 13 to 19 are formed by starting with the Greek word for the number of ones, followed by και (the Greek word for 'and'), followed by δέκα (the Greek word for 'ten').
Chemical symbols are the abbreviations used in chemistry, mainly for chemical elements; but also for functional groups, chemical compounds, and other entities. Element symbols for chemical elements, also known as atomic symbols , normally consist of one or two letters from the Latin alphabet and are written with the first letter capitalised.
The standard state of a material (pure substance, mixture or solution) is a reference point used to calculate its properties under different conditions.A degree sign (°) or a superscript Plimsoll symbol (⦵) is used to designate a thermodynamic quantity in the standard state, such as change in enthalpy (ΔH°), change in entropy (ΔS°), or change in Gibbs free energy (ΔG°).
A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus (+) and minus (−) signs.
In electrochemistry, lambda also denotes the ionic conductance of a given ion (the composition of the ion is generally shown as a subscript to the lambda character). In neurobiology, lambda denotes the length constant (or exponential rate of decay) of the electric potential across the cell membrane along a length of a nerve cell's axon.
Because the S 2− anion has a subscript of 2 in the formula (giving a 4− charge), the compound must be balanced with a 4+ charge on the Pb cation (lead can form cations with a 4+ or a 2+ charge). Thus, the compound is made of one Pb 4+ cation to every two S 2− anions, the compound is balanced, and its name is written as lead(IV) sulfide .
pH has no fundamental meaning; its official definition is a practical one. However, in the restricted range of dilute aqueous solutions having amount-of-substance concentrations less than 0.1 mol/L, and being neither strongly alkaline nor strongly acidic (2 < pH < 12), the definition is such that pH = −log 10 [c(H +) y 1 / (1 mol/L)] ± 0.02