Chemistry Questions & Answers

The reaction between aqueous strontium chloride \( \left(\mathrm{SrCl}_{2}\right) \) and aqueous potassium sulfate \( \left(\mathrm{K}_{2} \mathrm{SO}_{4}\right) \) forms a precipitate of strontium sulfate \( \left(\mathrm{SrSO}_{4}\right) \). Which of the following represents the net ionic equation for the reaction? (Topic 4.2) \( \mathrm{Sr}^{2+}(a q)+\mathrm{SO}_{4}^{2-}(a q) \rightarrow \mathrm{SrSO}_{4}(s) \) \( \mathrm{Sr}^{2+}(a q)+2 \mathrm{Cl}^{-}(a q)+\mathrm{SO}_{4}^{2-}(a q)+2 \mathrm{~K}^{+}(a q) \rightarrow \mathrm{SrSO}_{4}(s)+2 \mathrm{Cl}^{-}(a q)+2 \mathrm{~K}^{+}(a q) \) \( \mathrm{SrCl}_{2}(a q)+\mathrm{K}_{2} \mathrm{SO}_{4}(a q) \rightarrow \mathrm{SrSO}_{4}(s)+2 \mathrm{KCl}(a q) \) \( \mathrm{Cl}^{-}(a q)+\mathrm{K}^{+}(a q) \rightarrow \mathrm{KCl}(a q) \)

Equal volumes of 0.2 M solutions of lead(II) nitrate and potassium bromide are combined to form lead(II) bromide as a yellow precipitate. Which of the following is the correct net ionic equation for the reaction? (Topic 4.2) \( \mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}(a q)+2 \mathrm{KBr}(a q) \rightarrow \mathrm{PbBr}_{2}(s)+2 \mathrm{KNO}_{3}(a q) \) \( \mathrm{Pb}^{2+}(a q)+2 \mathrm{NO}_{3}^{-}(a q)+2 \mathrm{~K}^{+}(a q)+2 \mathrm{Br}(a q) \rightarrow 2 \mathrm{~K}^{+}(a q)+2 \mathrm{NO}_{3}^{-}(a q)+\mathrm{PbBr}_{2}(s) \) \( \mathrm{K}^{+}(a q)+\mathrm{NO}_{3}^{-}(a q) \rightarrow \mathrm{KNO}_{3}(a q) \) \( \mathrm{Pb}^{2+}(a q)+2 \mathrm{Br}(a q) \rightarrow \mathrm{PbBr}_{2}(s) \)

Which of the following is the net ionic equation for the reaction between aqueous sodium fluoride and hydrochloric acid? (Topic 4.2) \( \mathrm{F}^{-}(a q)+\mathrm{H}^{+}(a q) \rightarrow \mathrm{HF}(a q) \) \( \mathrm{Na}^{+}(a q)+\mathrm{Cl}^{-}(a q) \rightarrow \mathrm{NaCl}(a q) \) \( \mathrm{Na}^{+}(a q)+\mathrm{F}^{-}(a q)+\mathrm{H}^{+}(a q)+\mathrm{Cl}^{-}(a q) \rightarrow \mathrm{Na}^{+}(a q)+\mathrm{Cl}^{-}(a q)+\mathrm{HF}(a q) \) \( \mathrm{NaF}^{-}(a q)+\mathrm{HCl}(a q) \rightarrow \mathrm{NaCl}(a q)+\mathrm{HF}(a q) \)

What did Rutherford determine about the structure of the atom from his gold-foil experiment? Is each of the following statements true or false? a. A proton is attracted to an electron.

1 Formula 3.34 points Calculate the enthalpy for this reaction to the nearest whole number \( 2 \mathrm{C}(\mathrm{s})+\mathrm{H}_{2}(\mathrm{~g}) \cdots \mathrm{C}_{2} \mathrm{H}_{2}(\mathrm{~g}) \Delta \mathrm{H}^{\circ}=? ? ? \mathrm{~kJ} \) Given the following thermochemical equations: \[ \begin{array}{ll}\mathrm{C}_{2} \mathrm{H}_{2}(\mathrm{~g})+(5 / 2) \mathrm{O}_{2}(\mathrm{~g}) \cdots 2 \mathrm{CO}_{2}(\mathrm{~g})+\mathrm{H}_{2} \mathrm{O}(\ell) & \Delta \mathrm{H}^{\circ}=-1,270 \mathrm{~kJ} \\ \mathrm{C}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{~g}) \cdots>\mathrm{CO}_{2}(\mathrm{~g}) & \Delta \mathrm{H}^{\circ}=-327 \mathrm{~kJ} \\ \mathrm{H}_{2}(\mathrm{~g})+(1 / 2) \mathrm{O}_{2}(\mathrm{~g}) \cdots \mathrm{H}_{2} \mathrm{O}(\ell) & \Delta \mathrm{H}^{\circ}=-238 \mathrm{~kJ}\end{array} \]

a) \( \mathrm{NaCl} \rightarrow \mathrm{HCl} \rightarrow \mathrm{FeCl}_{2} \rightarrow \mathrm{FeCl}_{3} \rightarrow \mathrm{AgCl} \) 6) \( \mathrm{KBr} \rightarrow \mathrm{Br}_{2} \rightarrow \mathrm{ZnBr}_{2} \rightarrow \mathrm{HBr} \rightarrow \mathrm{Br}_{2} \rightarrow \mathrm{NaBrO}_{3} \) Для реакций, протекающих в растворах, запишите

(x Solutions of aluminum nitrate and sodium sulfate react to form sodium nitrate and aluminum sulfate. Classify this reaction. \( 2 \mathrm{Al}\left(\mathrm{NO}_{3}\right)_{3(\mathrm{aq})}+3 \mathrm{Na}_{2} \mathrm{SO}_{4(\mathrm{aq})} \rightarrow \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3(\mathrm{~s})}+6 \mathrm{NaNO}_{3(\mathrm{aq})} \)

4. ¿Qué compuesto es un hidróxido? \( \begin{array}{ll}\text { A) } \mathrm{H}_{2} \mathrm{SO}_{4} & \mathrm{NaOH} \\ \text { C) } \mathrm{CO}_{2} & \text { D) } \mathrm{HCl} \\ \text { 5. ¿Cuál es la nomenclatura sistemática del dióxido de carbono? } \\ \text { B) } \mathrm{CO}_{2}\end{array} \)

2. ¿Qué ion liberan los ácidos en solución acuosa? \( \begin{array}{ll}\text { A) } \mathrm{OH}^{-} & \text {() } \mathrm{H}^{+} \\ \text {C) } \mathrm{Na}^{+} & \text {D) } \mathrm{Cl}^{-}\end{array} \)

\( \begin{array}{ll}\text { 7. ¿Cuál es la fórmula del ácido acético? } & \mathrm{B}_{2} \mathrm{CH}_{3} \mathrm{COOH} \\ \text { A) } \mathrm{H}_{2} \mathrm{CO}_{3} & \text { D) } \mathrm{H}_{3} \mathrm{C}_{2} \mathrm{O}_{2} \\ \text { C) } \mathrm{HCOOH} & \end{array} \)