. Mg(s) + 2 H+(aq) – Mg2+(aq) + H2(g)
An experiment is done to find the volume of H2(g)
that is formed when a certain mass of Mg(s) reacts
with excess hydrochloric acid. The net ionic
equation for this reaction is shown. The experiment
is run with a 0.042-gram sample of pure Mg(s) and a
solution of 2.0 M hydrochloric acid.
Calculate the number of moles of Mg in the 0.0420 g sample.

Darla claims that the first periodic table developed by mendeleev was not completely accurate, so it is not useful at all. harmony argues that it establish the periodic table we use today, making it more credible. who is correct and why? darla is correct, because a model that has any mistakes should be thrown out. darla is correct, because a good model would not need to change. harmony is correct, because mendeleev’s model had all of the information correct in the first version. harmony is correct, because mendeleev’s model made predictions that came true.

The volume of helium in a blimp is 6.28 x 10^9 millimeters. the density of helium in the blimp is .1786 kilogram/meter^3. find the mass of the helium in the blimp.

What is true for a substance that releases energy