Also known as the Pearson product-moment correlation coefficient, the correlation coefficient (r) measures the linear relationship between two variables, with a value range of -1 to 1. A value close to 1 indicates there is a strong positive linear correlation between two variables; that is, when one variable increases so does the other.
A short definition. Delta H of a reaction is the enthalpy of reaction. H of products minus H of reactants. Each compound has a delta H of formation (dHf). The heats of formation for each substance in a reaction can be added together to compute the energy change for a reaction.
Delta is a Greek letter [math]\Delta[/math]. Apparently it was derived from the Phoenician letter dale, https://en.wikipedia.org/wiki/Dalet, which looks the same except turned 90Â°. That, in turn, is said to be based on a hieroglyph for door: Written Jun 26 â¢ View Upvotes.