Determine the number of moles in 4.50 × 10²³ formula units of CaBr₂

The molecular formula of acetylsalicylic acid (aspirin), one of the most commonly used pain relievers, is C9H8O4. a. Calculate the molar mass of aspirin. b. A typical aspirin tablet contains 500. mg C9H8O4. What amount (moles) of C9H8O4 molecules and what number of molecules of acetylsalicylic acid are in a 500.-mg tablet?

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.

Calculate the molar mass of the following substances. a. b. c. (NH4)2Cr2O7

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.)

Boron forms an extensive series of compounds with hydrogen, all with the general formula BxHy. To analyze one of these compounds, you burn it in air and isolate the boron in the form of B2O3 and the hydrogen in the form of water. You find that 0.1482 g BxHy gives 0.4221 g B2O3 when burned in excess O2. Determine the empirical I formula of BxHy.

2. An organic compound has an empirical formula CH2O and a molar mass of 180 g/mol. What is its molecular formula? CH2O C6H12O6 C2H4O2 C5H10O5

How many moles of beryllium (Be) are needed to completely react with 10.0 moles of N2 in the synthesis of the compound Be3N2?

Calculate the molar mass of the following substances. a. b. Ca3(PO4)2 c. Na2HPO4

Hydrogen cyanide is produced industrially from the reaction of gaseous ammonia, oxygen, and methane: 2NH3(g)+3O2(g)+2CH4(g)2HCN(g)+6H2O(g) If 5.00 103 kg each of NH3, O2, and CH4 are reacted, what mass of HCN and of H2O will be produced, assuming 100% yield?