The activation energy of a chemical reaction is the energy that

why do chemist use relative masses of atoms compared to a refference isotope rather than the actual of the atoms

An English unit used in pharmaceutical work is the grain (gr). There are 15 grains in 1 gram. An aspirin tablet contains 5.0 gr of aspirin. A 145 lb person takes two aspirin tablets.

Opal is a hydrated form of silica. If a laboratory analysis of a sample of opal reveals it to contain29.2% Si, 33.3%O, and 37.5% H 22 O, what is its empirical formula?

There are three competing factors at play here: 1. The effective nuclear charge 2. The size of the atom and the force of attraction according to Coulomb's law 3.

What evidence indicates that a reaction has occurred? (Select all that apply.) a. The temperature decreased. b. A solid brown product formed. c. The temperature increased. d. A gas formed. e. An explosion occurred.

Which of the following examples illustrates an object with kinetic energy?

A Chemist measured 184 mL using a graduated cylinder. Based on her experience, the volume did not seem to be correct.

What is the mass of a 1.00cm3 piece of iron having a density of 7.90g/cm3

When repeated measurements of the same quantity are very close to one another they are

A beaker has a mass of 77.275 calculate this mass in mg