Consider the 4 chemical reactions below. I. 2 H2O2(ℓ) → 2 H2O(ℓ) + O2(g)
II. N2(g) + 3 H2(g) → 2 NH3(g)
III. CaCO3(s) → CaO(s) + CO2(g)
IV. SO2(g) + H2O(ℓ) → H2SO3(aq)
For which reaction(s) will ∆S be negative?

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.

Ascientist is measuring the pressure that is exerted by each of the following gases in the atmosphere: carbon dioxide, oxygen, and nitrogen. which term most likely describes what she is measuring?

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ