Let's say say there are n1 mols of helium in the first balloon and n2 mols of nitrogen in the second one, which are equivalent to m1 grams of helium and m2 grams of nitrogen.
The molar mass of hydrogen is thus M1=m1/n1, same for nitrogen M2=m2/n2 hence the ratio of their masses is m1/m2=(M1n1)/(M2n2). Since both gases are rather similar, we can assume that n1~n2 hence m1/m2=M1/M2
Answer:
We can tell by how the continents look. Scientists who propose the pangea theory have said this. You can see for yourself because all the continents look like puzzle pieces you could put together. Scientists can also tell from the species. For example, let's say a scientist found a bone of a creature at the edge of a continent, the edge of another would have the same species. They have also calculated that the continents in itself are still splitting apart, but very slowly. The reason they split up was because tectonic plate movements.
.009375 kg or 9.375 grams will remain