The only definite evidence of a chemical reaction is

A) The production of new substances

B) Changes in phase

C) Formation of a gas

D) A color change

Bromine (Br2) is produced by reacting sea water with chlorine (Cl2) by the following reaction. What mass of Cl2 (in kg) is needed to produce 1.0 kg of Br2?

What is the first step when calculating the molar mass of a compound? A. multiply the total number of atoms in the compound by the compound by the combined molar mass. B. Add the total number of atoms for each element of the compound together. C.

An element's atomic number is equal to its number of

Which bond is broken when energy is released?

What is the oxidation state of h2

What is the average surface temperature of Uranus

Consider the following statements. A. Molecules of hot water have less kinetic energy than those of cold water. B. For most solids, solubility increases when temperature increases. C.

Which describes the fourth state of matter known as plasma? A It is a liquid containing nuclei and electrons. B It is a gas containing nuclei and electrons. C It is a liquid containing electrons created by fusion.

The process of using dna to produce complementary rna molecules is called

A substance contains 36.1 percent calcium and 63.9 percent chlorine by weight. What is the empirical formula of the given compound? A. CaCl B. Ca0.9Cl1.8 C. CaCl2 D. Ca2Cl4