1.5g of a sample containing chromium (Cr) gave 0.220g of Cr2O3 when suitably oxidized. What is the approximate percentage by mass? The answer is 10 but I don't know how to get the answer.

In a sample of oxygen gas at room temperature, the average kinetic energy of all the balls stays constant. which postulate of kinetic molecular theory best explains how this is possible? a. attractive forces between gas particles are negligible because the particles of an ideal gas are moving so quickly. b. collisions between gas particles are elastic; there is no net gain or loss of kinetic energy. c. gases consist of a large number of small particles, with a lot of space between the particles. d. gas particles are in constant, random motion, and higher kinetic energy means faster movement.

Liv sheldon given the balanced equation for an organic reaction: c2h2 + 2cl2 → c2h2cl4 this reaction is best classified as *

Which statement can best be concluded from the ideal gas law?