Calculate the number of molecules of C2B formed

Calculate the moles of anhydrous (dry) KAl(SO4)2 that were present in the sample and the ratio of moles of H2O to moles of anhydrous KAl(SO4)2. Write the empirical formula for the hydrated KAl(SO4)2

Use the following theoretical equation A2B3 + 3 C2D --> A2D3 + 3 C2B (OR A2 B3 + 3 C2 D right arrow A2 D3 + 3 C2 B) Calculate the number of molecules of C2B formed from the reaction of (1.60000x10^1) grams of A2B3 and (1.376x10^3) grams of C2D The atomic weight of A is 15.0 grams/mol The atomic weight of B is 50.0 grams/mol The atomic weight of C is 35.0 grams/mol The atomic weight of D is 120.0 grams/mol Avogadro's number is (6.02200x10^23)

A 3.000 g sample of a gaseous compound was found to contain 2.560 g of carbon and 0.440 g of hydrogen. A) What is the simplest formula of the compound (Write C first and then H)? You won't be able to make the numbers a subscript. For instance, for MgCl2 enter MgCl2. B) The molar mass of the compound was found to be 42.08 g/mol. What is the molecular formula of the compound? You won't be able to make the numbers a subscript. For instance, for MgCl2 enter MgCl2.

If you react 6.64g of Chromium with sulfuric acid, you produce hydrogen gas and Cr₂SO4. How much Cr₂SO4 did you actually produce if your %yield was only 93% ? (Use the following atomic masses: Cr= 52; S = 32; O = 16; and H= 1 g/mole) Do answer with two decimal places.

4Fe+3O2-> 2Fe2O3  if 44.2 grams of oxygen react with an excess of iron, what mass of Fe2O3 can form? (Fe2O3=159.70 g/mol)

When 7.045 g of one of the hydrates of sodium sulfate (Na2SO4) was heated to drive off its water of hydration, the residue of anhydrous sodium sulfate has a mass of 4.674 g. What is the value of x in the formula for the hydrate, Na2SO4•xH2O?

Please solve the problem on the picture showing step by step and why is like that.