What is the difference in mass between 1.5x1023 molecules of sulfur dioxide and 7.0 moles of hydrogen gas?

To answer this question, we need to know the molar mass of sulfur dioxide (SO2) and hydrogen gas (H2).

1. The molar mass of SO2 is approximately 64.07 g/mol (32.07 g/mol for S and 16.00 g/mol for each O).
2. The molar mass of H2 is approximately 2.02 g/mol (1.01 g/mol for each H).

Next, we need to convert the number of molecules to moles for SO2.

3. Avogadro's number tells us that there are approximately 6.022 x 10^23 molecules in one mole. So, 1.5 x 10^23 molecules of SO2 is (1.5 x 10^23) / (6.022 x 10^23) = 0.249 moles.

Now we can find the mass of each substance.

4. The mass of SO2 is (0.249 moles) x (64.07 g/mol) = 15.97 g.
5. The mass of H2 is (7.0 moles) x (2.02 g/mol) = 14.14 g.

Finally, subtract the mass of H2 from the mass of SO2 to find the difference.

6. The difference in mass is 15.97 g - 14.14 g = 1.83 g.

So, there is a difference of 1.83 grams between 1.5 x 10^23 molecules of sulfur dioxide and 7.0 moles of hydrogen gas.