Chapter 7

Outline the steps needed to determine the limiting reactant when 0.50 mol of \(\mathrm{Cr}\) and \(0.75 \mathrm{mol}\) of \(\mathrm{H}_{3} \mathrm{PO}_{4}\) react according to the following chemical equation. \(2 \mathrm{Cr}+2 \mathrm{H}_{3} \mathrm{PO}_{4} \longrightarrow 2 \mathrm{CrPO}_{4}+3 \mathrm{H}_{2}\) Determine the limiting reactant.

How many molecules of \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{Cl}_{2}\) can be prepared from \(15 \mathrm{C}_{2} \mathrm{H}_{4}\) molecules and \(8 \mathrm{Cl}_{2}\) molecules?

What volume of 0.0105-M HBr solution is required to titrate 125 mL of a 0.0100-M Ca(OH)_solution? \(\mathrm{Ca}(\mathrm{OH})_{2}(a q)+2 \mathrm{HBr}(a q) \rightarrow \mathrm{CaBr}_{2}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l)\)

Titration of a 20.0-mL sample of acid rain required 1.7 mL of 0.0811 M NaOH to reach the end point. If we assume that the acidity of the rain is due to the presence of sulfuric acid, what was the concentration of sulfuric acid in this sample of rain?

What is the concentration of \(\mathrm{NaCl}\) in a solution if titration of \(15.00 \mathrm{mL}\) of the solution with \(0.2503 \mathrm{M} \mathrm{AgNO}_{3}\) requires 20.22 mL of the AgNO_ solution to reach the end point? \(\mathrm{AgNO}_{3}(a q)+\mathrm{NaCl}(a q) \rightarrow \mathrm{AgCl}(s)+\mathrm{NaNO}_{3}(a q)\)

In a common medical laboratory determination of the concentration of free chloride ion in blood serum, a serum sample is titrated with a \(\mathrm{Hg}\left(\mathrm{NO}_{3}\right)_{2}\) solution. \(2 \mathrm{Cl}^{-}(a q)+\mathrm{Hg}\left(\mathrm{NO}_{3}\right)_{2}(a q) \rightarrow 2 \mathrm{NO}_{3}^{-}(a q)+\mathrm{HgCl}_{2}(s)\) What is the \(\mathrm{Cl}^{-}\) concentration in a 0.25 -mL sample of normal serum that requires \(1.46 \mathrm{mL}\) of \(8.25 \times 10^{-4} \mathrm{M}\) \(\mathrm{Hg}\left(\mathrm{NO}_{3}\right)_{2}(a q)\) to reach the end point?

A 0.025-g sample of a compound composed of boron and hydrogen, with a molecular mass of 28 amu, bums spontaneously when exposed to air, producing \(0.063 \mathrm{g}\) of \(\mathrm{B}_{2} \mathrm{O}_{3} .\) What are the empirical and molecular formulas of the compound?

What volume of 0.600 M HCl is required to react completely with 2.50 g of sodium hydrogen carbonate? \(\mathrm{NaHCO}_{3}(a q)+\mathrm{HCl}(a q) \rightarrow \mathrm{NaCl}(a q)+\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l)\)

What volume of \(0.08892 M\) HNO \(_{3}\) is required to react completely with 0.2352 g of potassium hydrogen phosphate? \(2 \mathrm{HNO}_{3}(a q)+\mathrm{K}_{2} \mathrm{HPO}_{4}(a q) \rightarrow \mathrm{H}_{2} \mathrm{PO}_{4}(a q)+2 \mathrm{KNO}_{3}(a q)\)

What volume of a 0.3300-M solution of sodium hydroxide would be required to titrate 15.00 mL of 0.1500 M oxalic acid? \(\mathrm{C}_{2} \mathrm{O}_{4} \mathrm{H}_{2}(a q)+2 \mathrm{NaOH}(a q) \rightarrow \mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l)\)

What volume of a 0.00945-M solution of potassium hydroxide would be required to titrate 50.00 mL of a sample of acid rain with a \(\mathrm{H}_{2} \mathrm{SO}_{4}\) concentration of \(1.23 \times 10^{-4} \mathrm{M}\) \(\mathrm{H}_{2} \mathrm{SO}_{4}(a q)+2 \mathrm{KOH}(a q) \longrightarrow \mathrm{K}_{2} \mathrm{SO}_{4}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l)\)

A sample of solid calcium hydroxide, \(\mathrm{Ca}(\mathrm{OH})_{2},\) is allowed to stand in water until a saturated solution is formed. A titration of \(75.00 \mathrm{mL}\) of this solution with \(5.00 \times 10^{-2} \mathrm{M}\) HCl requires \(36.6 \mathrm{mL}\) of the acid to reach the end point. \(\mathrm{Ca}(\mathrm{OH})_{2}(a q)+2 \mathrm{HCl}(a q) \rightarrow \mathrm{CaCl}_{2}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l)\) What is the molarity?

The reaction of \(\mathrm{WCl}_{6}\) with \(\mathrm{Al}\) at \(\sim 400^{\circ} \mathrm{C}\) gives black crystals of a compound containing only tungsten and chlorine. A sample of this compound, when reduced with hydrogen, gives 0.2232 g of tungsten metal and hydrogen chloride, which is absorbed in water. Titration of the hydrochloric acid thus produced requires \(46.2 \mathrm{mL}\) of \(0.1051 \mathrm{M}\) NaOH to reach the end point. What is the empirical formula of the black tungsten chloride?