Problem 1
Assume that matter does not consist of atoms. Show by example how this assumption leads to hypothetical predictions which contradict the Law of Multiple Proportions. Do the se hypothetical examples contradict the Law of Definite Proportions? Are both observations required for confirmation of the atomic theory?
Problem 2
Two compounds, A and B, are formed entirely from hydrogen and carbon. Compound A is \(80.0 \%\) carbon by mass, and \(20.0 \%\) hydrogen, whereas Compound \(\mathrm{B}\) is \(83.3 \%\) carbon by mass and \(16.7 \%\) hydrogen. Demonstrate that these two compounds obey the Law of Multiple Proportions. Explain why the se results strongly indicate that the elements carbon and hydrogen are composed of atoms.
Problem 3
In many chemical reactions, mass does not appear to be a conserved quantity. For example, when a tin can rusts, the resultant rusty tin can has a greater mass than before rusting. When a candle burns, the remaining candle has invariably less mass than before it was burned. Provide an explanation of these observations, and describe an experiment which would demonstrate that \(\mathrm{m}\) ass is actually conserved in these chemical reactions.
Problem 4
The following question was posed on an exam: An unknown non-metal element (Q) forms two gaseous fluorides of unknown molecular formula. A \(3.2 \mathrm{~g}\) sample of \(Q\) reacts with fluorine to form \(10.8 \mathrm{~g}\) of the unknown fluoride \(A . A 6.4 \mathrm{~g}\) sample of \(Q\) reacts with fluorine to form \(29.2 \mathrm{~g}\) of unknown fluoride \(B\). Using these data only, demonstrate by calculation and explanation that these unknown compounds obey the Law of Multiple Proportions.
