Which of the following is NOT a reason why index fossils are chosen for determining ages of rocks? Select all that apply. A. Found commonly in rocks

B. Distributed over a very wide range

C. Are always dinosaurs

D. Limited life existence in geologic time. Single choice.
(10 Points)
A
B
C
D

Which class of molecules functions as chemical signals? hormones water carbohydrates proteins

When hydrochloric acid reacts with potassium hydroxide solution, the following reaction occurs. hcl (aq) + koh (aq) h2o (l) + kcl (aq) the reaction gives off heat energy, so it is an reaction.

Cryolite, na3alf6(s), an ore used in the production of aluminum, can be synthesized using aluminum oxide. start this question by first balance the chemical equation.1.) balance the equation: - alo3(s)+naoh(l)+hf(> na3alf6+h2o(g). 2.) if 17.5 kilograms of al2o3(s), 51.4 kilograms of naoh(l), and 51.4 kilograms of hf(g) react completely, how many kilograms of cryolite will be produced? 3.)which reactants will be in excess, (al2o3, naoh, or hf) 4.)what is the total mass of the excess reactants left over after the reaction is complete in kg?