find mass of sulfuric acid obtained in reaction of 20.0g if sulfur trioxide with excess of water

We don't do all of your homework for you. The idea is to help so you can do it yourself. The problem with CaO to CaCO3 is worked the same way as this problem. You try it. I'll be more than happy to check your work and answers. Also, if you don't understand something about the CaCO3 problem or this one I'll be glad to help you through it.

to be honest I don't understand any of it I have a foreign chemistry teacher and I am not getting any of it.

To find the mass of sulfuric acid obtained in the reaction, you need to first write and balance the chemical equation for the reaction. The reaction between sulfur trioxide (SO3) and water (H2O) produces sulfuric acid (H2SO4):

SO3 + H2O → H2SO4

The equation tells us that one mole of SO3 reacts with one mole of H2O to produce one mole of H2SO4.

Next, you need to determine the molar mass of SO3. Sulfur (S) has an atomic mass of 32.06 g/mol, and oxygen (O) has an atomic mass of 16.00 g/mol. Since there are three oxygen atoms in SO3, the molar mass of SO3 is:

32.06 g/mol (Sulfur) + 3 × 16.00 g/mol (Oxygen) = 80.06 g/mol

Now, use the molar mass of SO3 to calculate the number of moles of SO3:

Number of moles of SO3 = Mass of SO3 / Molar mass of SO3
= 20.0 g / 80.06 g/mol
= 0.2497 mol (rounded to four decimal places)

Since the reaction is given to have occurred with an excess of water, it means that all the SO3 has reacted and been converted to H2SO4.

Finally, we can use the balanced chemical equation to determine the molar mass of H2SO4. Hydrogen (H) has an atomic mass of 1.01 g/mol, sulfur (S) has an atomic mass of 32.06 g/mol, and oxygen (O) has an atomic mass of 16.00 g/mol. Thus, the molar mass of H2SO4 is:

2 × 1.01 g/mol (Hydrogen) + 32.06 g/mol (Sulfur) + 4 × 16.00 g/mol (Oxygen) = 98.09 g/mol

Now, use the molar mass of H2SO4 and the number of moles of SO3 to calculate the mass of sulfuric acid obtained:

Mass of H2SO4 = Number of moles of SO3 × Molar mass of H2SO4
= 0.2497 mol × 98.09 g/mol
= 24.49 g (rounded to two decimal places)

Therefore, the mass of sulfuric acid obtained in the reaction is approximately 24.49 grams.