If you were presented with 2l of a 2m sucrose stock solution, how many grams of sugar would be in a 100 ml aliquot?

The 2 L of sucrose stock solution would contain similar concentration with the 100 mL aliquot. Therefore the concentration of aliquot is still 2 M.

The molar mass of sucrose is 342.3 g / mol. Therefore the mass in a 100 mL (0.1 L) aliquot is:

mass = (2 mol / L) * 0.1 L * (342.3 g / mol)

mass = 68.46 g

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.