What is the mass, in grams, of 4.06 1023 molecules of aspirin, C9H8O4?

Chlorine exists mainly as two isotopes, 37Cl and 33Cl. Which is more abundant? How do you know?

Tungsten (W) metal, which is used to make incandescent bulb filaments, is produced by the reaction WO3+3H23H2O+W How many grams of H2 are needed to produce 1.00 g of W?

A sample of sandstone consists of silica, SiO2, and calcite, CaCO3. When the sandstone is heated, calcium carbonate, CaCO3, decomposes into calcium oxide, CaO, and carbon dioxide CaCO3(s)CaO(s)+CO2(g) What is the percentage of silica in the sandstone if 18.7 mg of the rock yields 3.95 mg of carbon dioxide?

You take 1.00 g of an aspirin tablet (a compound consisting solely of carbon, hydrogen, and oxygen), burn it in air, and collect 2.20 g CO2 and 0.400 g H2O. You know that the molar mass of aspirin is between 170 and 190 g/mol. Reacting 1 mole of salicylic acid with I mole of acetic anhydride (C4H6O3) gives you 1 mole of aspirin and 1 mole of acetic acid (C2H4O2). Use this information to determine the molecular formula of salicylic acid.

A mixture of Fe2O3, and FeO was found to contain 72.00% Fe by mass. What is the mass of Fe2O3 in 0.750 g of this mixture?

Phosphoric acid, H3PO4, can be prepared by the reaction of phosphorus(V) oxide, P4O10, with water. 14P4O10(s)+32H2O(l)H3PO4(aq);H=96.2kJ What is H for the reaction involving 1 mol of P4O10? P4O10(s)+6H2O(l)4H3PO4(aq)

The active ingredient in Pepto-Bismo® (an over- the-counter remedy for an upset stomach) is bismuth sub-salicylate, C7H5BiO4. Analysis of a 1.7500-g sample of Pepto-Bismol yields 346 mg of bismuth. What percent by mass is bismuth subsalicylate in the sample? (Assume that there are no other bismuth-containing compounds in Pepto-Bismol.)

3.96 Methyl cyanoacrylate is the chemical name for the substance sold as Super Glue, and it has the chemical formula C5H5NO2. Calculate the number of molecules of this substance in a 1.0-ounce tube of Super Glue, assuming that the glue is 80% methyl cyanoacrylate by mass.

4.108 Elemental analysis is sometimes carried out by combustion of the sample. For a hydrocarbon, the only products formed are CO2 and H2O. If a 1.36-g sample of an unknown hydrocarbon is burned and 2.21 g of H2O is produced along with 4.07 g of CO2, what is the empirical formula of the hydrocarbon?