A 3.50 g of an alloy which contains only lead and tin is dissolved in hot HNO3. Excess sulfuric acid is added to this solution and 1.57g of PbSO4(s) is obtained. (b) Assuming all the lead in the alloy reacted to form PbSO4, what was the amount, in grams, of lead and tin in the alloy respectively?

(b) Because atoms are spherical, they cannot occupy all of the space of the cube. The silver atoms pack in the solid in such a way that 74% of the volume of the solid is actually filled with the silver atoms. Calculate the volume of a single silver atom.

Hydrogen cyanide, HCN, is a poisonous gas. The lethal dose is approximately 300 mg HCN per kilogram of air when inhaled. (a) Calculate the amount of HCN that gives the lethal dose in a small laboratory room measuring 3.5 × 4.5 × 2.5 m. The density of air at 26 °C is 0.00118 g/cm³. (b) If the HCN is formed by reaction of NaCN with an acid such as H₂SO₄, what mass of NaCN gives the lethal dose in the room? 2 NaCN(s) + H₂SO₄(aq) → Na₂SO₄(aq) + 2 HCN(g)

Hydrogen cyanide, HCN, is a poisonous gas. The lethal dose is approximately 300 mg HCN per kilogram of air when inhaled. (c) HCN forms when synthetic fibers containing Orlon® or Acrilan ® burn. Acrilan® has an empirical formula of CH₂CHCN, so HCN is 50.9% of the formula by mass. A rug measures 3.5 × 4.5 m and contains 850 g of Acrilan® fibers per square yard of carpet. If the rug burns, will a lethal dose of HCN be generated in the room? Assume that the yield of HCN from the fibers is 20% and that the carpet is 50% consumed.

The source of oxygen that drives the internal combustion engine in an automobile is air. Air is a mixture of gases, principally N₂(79%) and O₂(20%). In the cylinder of an automobile engine, nitrogen can react with oxygen to produce nitric oxide gas, NO. As NO is emitted from the tailpipe of the car, it can react with more oxygen to produce nitrogen dioxide gas. (a) Write balanced chemical equations for both reactions.

Burning acetylene in oxygen can produce three different carbon-containing products: soot (very fine particles of graphite), CO(g), and CO₂(g). (c) Why, when the oxygen supply is adequate, is CO₂(g) the predominant carbon-containing product of the combustion of acetylene?