A student measures a boiling water bath with two different thermometers. The digital thermometer records the temperature as 100.2°C and has an uncertainty of 0.1°C. The analog thermometer records the temperature as 99.0°C and has an uncertainty of 0.5°C. What is the percent uncertainty of each thermometer? And what is the percent error given that water boils at 100.0°C?

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.