22. How many Na+ ions are in a mole of Na2SO4 ? How many SO4²- ions?

3.123 Most periodic tables provide molar masses with four or five significant figures for the elements. How accurately would you have to measure the mass of a sample of roughly 100 g to make a calculation of the number of moles of the chemical to have its significant figures limited by the molar mass calculation rather than the mass measurement?

hat is the difference between the empirical and molecular for mulas of a compound? Can they ever be the same? Explain.

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.

The compound 1-propanethiol, which is the eye irritant released when fresh onions are chopped up, has the chemical formula C3HyS and a formula mass of 76.18 amu. What number does y stand for in the chemical formula of the compound?

n chemistry, what is meant by the term mole? What is the importance of the mole concept?

A substance X2Z has the composition (by mass) of 40.0% X and 60.0% Z. What is the composition (by mass) of the compound XZ2?

An Alka-Seltzer tablet contains 324 mg of aspirin (C.9H8O4,), 1904 mg of NaHCO3, and 1000. mg of citric add (H3C6H5O7). (The last two compounds react with each other to provide the "fizz," bubbles of CO2, when the tablet is put into water.) (a) Calculate the amount (moles) of each substance in the tablet. (b) If you take one tablet, how many molecules of aspirin are you consuming?

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

Calculate the mass in grams of 3.839 moles of (a) hydrazine, a rocket propellant. (b) caffeine, C4H5N2O. (c) theobromine, C7H8N4O2, the alkaloid present in chocolate and cocoa.