Problem 112
A balanced chemical equation contains the term \(" 3 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}\)." How many atoms of each element does this represent in the molecular view? How many moles of each element does this represent on the laboratory scale?
Problem 113
Chlorine is used by textile manufacturers to bleach cloth. Excess chlorine is destroyed by its reaction with sodium thiosulfate, \(\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\), as follows. $$ \begin{aligned} \mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}(a q)+4 \mathrm{Cl}_{2}(g)+5 \mathrm{H}_{2} \mathrm{O} \longrightarrow \\ 2 \mathrm{NaHSO}_{4}(a q)+8 \mathrm{HCl}(a q) \end{aligned} $$ (a) How many moles of \(\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\) are needed to react with \(0.12 \mathrm{~mol}\) of \(\mathrm{Cl}_{2}\) ? (b) How many moles of \(\mathrm{HCl}\) can form from \(0.12 \mathrm{~mol}\) of \(\mathrm{Cl}_{2} ?\) (c) How many moles of \(\mathrm{H}_{2} \mathrm{O}\) are required for the reaction $$ \text { of } 0.12 \mathrm{~mol} \text { of } \mathrm{Cl}_{2} ? $$ (d) How many moles of \(\mathrm{H}_{2} \mathrm{O}\) react if \(0.24 \mathrm{~mol} \mathrm{HCl}\) is formed?
Problem 114
The octane in gasoline burns according to the following equation. $$ 2 \mathrm{C}_{8} \mathrm{H}_{18}+25 \mathrm{O}_{2} \longrightarrow 16 \mathrm{CO}_{2}+18 \mathrm{H}_{2} \mathrm{O} $$ (a) How many moles of \(\mathrm{O}_{2}\) are needed to react fully with \(6.84 \mathrm{~mol}\) of octane? (b) How many moles of \(\mathrm{CO}_{2}\) can be formed from 0.511 mol of octane? (c) How many moles of water are produced by the combustion of \(8.20 \mathrm{~mol}\) of octane? (d) If this reaction is used to synthesize \(6.00 \mathrm{~mol}\) of \(\mathrm{CO}_{2}\), how many moles of oxygen are needed? How many moles of octane?
Problem 115
Propane burns according to the following equation: $$ \mathrm{C}_{3} \mathrm{H}_{8}+5 \mathrm{O}_{2} \longrightarrow 3 \mathrm{CO}_{2}+4 \mathrm{H}_{2} \mathrm{O} $$ (a) How many grams of \(\mathrm{O}_{2}\) are needed to react fully with \(3.45 \mathrm{~mol}\) of propane? (b) How many grams of \(\mathrm{CO}_{2}\) can form from \(0.177 \mathrm{~mol}\) of propane? (c) How many grams of water are produced by the combustion of \(4.86 \mathrm{~mol}\) of propane?
Problem 116
The following reaction is used to extract gold from pre-treated gold ore: \(2 \mathrm{Au}(\mathrm{CN})_{2}^{-}(a q)+\mathrm{Zn}(s) \longrightarrow 2 \mathrm{Au}(s)+\mathrm{Zn}(\mathrm{CN})_{4}^{-}(a q)\) (a) How many grams of \(Z n\) are needed to react with 0.11 mol of \(\mathrm{Au}(\mathrm{CN})_{2}^{-} ?\) (b) How many grams of Au can form from \(0.11 \mathrm{~mol}\) of \(\mathrm{Au}(\mathrm{CN})_{2}^{-} ?\) (c) How many grams of \(\mathrm{Au}(\mathrm{CN})_{2}^{-}\) are required for the reaction of \(0.11 \mathrm{~mol}\) of \(\mathrm{Zn}\) ?
Problem 117
The incandescent white of a fireworks display is caused by the reaction of phosphorus with \(\mathrm{O}_{2}\) to give \(\mathrm{P}_{4} \mathrm{O}_{10}\). (a) Write the balanced chemical equation for the reaction. (b) How many grams of \(\mathrm{O}_{2}\) are needed to combine with \(6.85 \mathrm{~g}\) of \(\mathrm{P} ?\) (c) How many grams of \(\mathrm{P}_{4} \mathrm{O}_{10}\) can be made from \(8.00 \mathrm{~g}\) of \(\mathrm{O}_{2} ?\) (d) How many grams of \(\mathrm{P}\) are needed to make \(7.46 \mathrm{~g}\) of \(\mathrm{P}_{4} \mathrm{O}_{10} ?\)
Problem 120
The reaction of hydrazine, \(\mathrm{N}_{2} \mathrm{H}_{4},\) with hydrogen peroxide, \(\mathrm{H}_{2} \mathrm{O}_{2},\) has been used in rocket engines. One way these compounds react is described by the equation $$ \mathrm{N}_{2} \mathrm{H}_{4}+7 \mathrm{H}_{2} \mathrm{O}_{2} \longrightarrow 2 \mathrm{HNO}_{3}+8 \mathrm{H}_{2} \mathrm{O} $$ According to this equation, how many grams of \(\mathrm{H}_{2} \mathrm{O}_{2}\) are needed to react completely with \(852 \mathrm{~g}\) of \(\mathrm{N}_{2} \mathrm{H}_{4} ?\)
Problem 122
Oxygen gas can be produced in the laboratory by decomposition of potassium chlorate \(\left(\mathrm{KClO}_{3}\right)\) $$ \mathrm{KClO}_{3}(s) \longrightarrow 2 \mathrm{KCl}(s)+3 \mathrm{O}_{2}(g) $$ How many \(\mathrm{kg}\) of \(\mathrm{O}_{2}\) can be produced from \(1.0 \mathrm{~kg}\) of \(\mathrm{KClO}_{3} ?\)
Problem 129
Some of the acid in acid rain is produced by the following reaction: $$ 3 \mathrm{NO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2 \mathrm{HNO}_{3}(a q)+\mathrm{NO}(g) $$ If a falling raindrop weighing \(0.050 \mathrm{~g}\) comes into contact with \(1.0 \mathrm{mg}\) of \(\mathrm{NO}_{2}(g)\), how many milligrams of \(\mathrm{HNO}_{3}\) can be produced?
Problem 131
Barium sulfate, \(\mathrm{BaSO}_{4}\), is made by the following reaction. \(\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}(a q)+\mathrm{Na}_{2} \mathrm{SO}_{4}(a q) \longrightarrow \mathrm{BaSO}_{4}(s)+2 \mathrm{NaNO}_{3}(a q)\) An experiment was begun with \(75.00 \mathrm{~g}\) of \(\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}\) and an excess of \(\mathrm{Na}_{2} \mathrm{SO}_{4}\). After collecting and drying the product, \(64.45 \mathrm{~g}\) of \(\mathrm{BaSO}_{4}\) was obtained. Calculate the theoretical yield and percentage yield of \(\mathrm{BaSO}_{4}\)
