Solid added to liquid and the solid floats down to bottom of container physical or chemical change?

In the cathode ray tube experiment, j. j. thomson passed an electric current through different gases inside a cathode ray tube in the presence of an electric field. in which two ways did this experiment change scientists’ understanding of the atom?

At stp, which substance is the best conductor of electricity? a. nitrogen b. neon c. sulfur d. silver

Pinene is an unsaturated hydrocarbon found in pine resin. if pinene has m+ = 136 and contains 1 double bond(s) and 2 ring(s); what is its molecular formula? enter the formula in the form ch first, then all other atoms in alphabetical order; do not use subscripts. the formula is case-sensitive