The mass of one mole of He is 4 grams. John’s experimental data indicated that the mass of 1 mole of He is 3.8 grams. What was his percent error? The density of nitrogen gas, N2, is 1.25 g/L. Laeni determined the density of N2 to be 1.35 g/L. What was her percent error?
Sean determined the volume of a penny to be 0.46mL. The teacher determined the volume of a penny to be 0.54mL. What was Sean’s percent error?

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Under normal conditions, describe how increasing the temperatures effects the solubility of a typical salt

What is the rate law for the uncatalyzed reaction?