Which mineral can be easily scratched by a finger nail, has cleavage, a metallic luster and has a black streak? 11. Which two elements are found in all minerals on the chart?

Kc = 0.040 for the system below at 450oc. if a reaction is initiated with 0.40 mole of cl2 and 0.40 mole of pcl3 in a 2.0 liter container, what is the equilibrium concentration of cl2 in the same system? pcl5(g) ⇄ pcl3(g) + cl2(g)

Why do the strengths of london (dispersion) forces generally increase with increasing molecular size? choose one: a. heavier atoms have stronger attractions for each other than lighter atoms. b. dispersion forces are all equal in magnitude; there is no size dependence. c. dispersion forces arise from the attraction between the nuclei of atoms, and larger molecules have larger nuclei. d. dispersion forces arise from dipoles caused by the electron distribution being distorted. larger molecules have more electrons and, therefore, more distortions and a bigger force. e. dispersion forces depend on distance. larger molecules are farther apart and so the forces are smaller.

1) a light bulb takes in 30 of energy per second. it transfers 3j as use energy. calculate the efficiency. second. it transfers 3j as useful light energy and 27j as heat energy. calculate the efficiency