endothermic
In endothermic reactions, the temperature of the products is typically lower than the temperature of the reactants. The drop in temperature may be great enough to cause liquids to freeze. Thats what happens in the endothermic reaction at this URL: http://www. bbc. co. uk/schools/gcsebitesize/science/add_aqa_pre_2011/chemreac/energychangesrev1. shtml .