Calculate the number of moles of ethanol present in 243.3 mL of ethanol, CH3CH2OH, which has a density of 0.789 g/mL.

1a) 1b)

Lead is found in Earth’s crust as several different lead ores. Suppose a certain rock is 38.0% PbS (galena), 25.0% PbCO3 (cerussite), and 17.4% PbSO4 (anglesite). The remainder of the rock is composed of substances containing no lead. How much of this rock (in kg) must be processed to obtain 5.0 metric tons of lead? (A metric ton is 1000 kg.)

A major component of honey is fructose (C6H12O6) with a molar mass of 180.16 g/mol. A tablespoon (15.0 mL) of honey is considered one serving. How many tablespoons must be eaten to consume 0.1900 moles of fructose? Assume honey is 100% fructose. The density of honey is 1.45 g/mL.

Vitamin C, an antioxidant present in citrus fruits, contains only C, H, and O. Combustion of 10.0 g of vitamin C produces 14.99 g of CO₂ and 4.092 g of H₂O. Determine the molar mass of the compound if it is between 150.0 and 220.0 g/mol. Provide an answer to four significant figures.

In the recipe for mayonnaise, the phospholipids in the egg yolk act as emulsifiers. If you assume that one egg yolk weighs 10g, that about 33% of this is fat, and that the majority of the fat is phospholipids. If you take the average molecular weight of a phospholipid to be 800 g/mol. How many phospholipid molecules are there in one egg yolk? Give your answer in molecules, but without entering the unit. Enter the number in scientific notation with the form #.#e##

calculate the number of molecules in 0.256 g of NH4Cl. (molar mass of NH4Cl = 53.492 g/mol; 1 mole = 6.02x10^23)

Aspirin can be prepared from salicylic acid (C7H6O3 ), which has a molar mass of 138.12 g/mol, and acetic anhydride (C4 H6 O3), which has a molar mass of 102.04 g/mol. The density of acetic anhydride is 1.082 g/mL. C;H,O3 + C4H6O3 → C9HgO4 + C2H3O2 What is the theoretical yield, in grams, of aspirin (C9H3O4), which has a molar mass of 180.15 g/mol, possible when reacting 3.06 g of salicylic acid with 3.71 mL of acetic anhydride? Type answer:

Without doing any detailed calculations (but using a periodic table to give atomic weights), rank the following samples in order of decreasing number of atoms: 0.50 mol H2O, 23g Na, 6.0 × 10^23 N2 molecules.   How do I do this?

An impure sample of table salt (NaCl) that was dissolved in water and treated with silver nitrate to form silver chloride. If the initial sample had a mass of 1.741 g and the final mass of the AgCl was found to be 4.084 g, what is the mass percent of NaCl in the impure sample?