1)why we use dilute acid in the preparation of H2 gas 2)why don't use HNO2, rather than use HCl and H2SO4 in the H2 gas preparation.​

What are the first three quantum numbers for the electrons located in subshell 2s?

The comparison of the number of atoms in a copper coin the size of a penny with the number of people on earth is made to illustrate which of the following? a. that atoms are indivisible b. that atoms are very small c. that atoms are very large d. that in a copper penny, there is one atom for every person on earth

Which can be observed only in a microscopic view? a) structure of a muscle cell b) shape of a soybean plant c) foam insulation d) x-ray of a knee joint