Why is 18-karat gold considered a mixture rather than a pure substance? a) it has a variable composition. b) its color is different than pure gold. c) the gold atoms are not arranged in a repeating pattern. d) it can be melted and transformed into a different substance

What is the name of this hydrocarbon?

Based on the equation and the information in the table, what is the enthalpy of the reaction?

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.