Química preguntas y respuestas

How is molarity measured? A. In moles of a substance dissolved in 1 L of water B. In moles of a substance for 1 g of that substance C. In liters of water per gram of a dissolved substance D. In liters of water per moles of a dissolved substance

What are the half-reactions for an electrolytic cell with aluminum and gold electrodes? \[ \begin{array}{l}\text { A. } \mathrm{Al}(s) \rightarrow \mathrm{Al}^{3+}(a q)+3 e^{-} \text {and } \mathrm{Au}^{+}(a q)+\mathrm{e}^{-} \rightarrow \mathrm{Au}(s) \\ \text { B. } \mathrm{Al}^{3+}(a q)+3 \mathrm{e}^{-} \rightarrow \mathrm{Al}(s) \text { and } \mathrm{Au}(s) \rightarrow \mathrm{Au}^{+}(a q)+\mathrm{e}^{-} \\ \text {C. } \mathrm{Al}^{3+}(a q)+3 \mathrm{e}^{-} \rightarrow \mathrm{Al}(s) \text { and } \mathrm{Au}^{+}(a q)+\mathrm{e}^{-} \rightarrow \mathrm{Au}(s) \\ \text { D. } \mathrm{Al}^{-}(s) \rightarrow \mathrm{Al}^{3+}(a q)+3 \mathrm{e}^{-} \text {and } \mathrm{Au}(s) \rightarrow \mathrm{Au}^{+}(a q)+\mathrm{e}^{-}\end{array} \]

What are the half-reactions for a galvanic cell with aluminum and gold electrodes? \[ \begin{array}{l}\text { A. } \mathrm{Al}^{3+}(a q)+3 \mathrm{e}^{-} \rightarrow \mathrm{Al}(s) \text { and } \mathrm{Au}^{+}(a q)+\mathrm{e}^{-} \rightarrow \mathrm{Au}(s) \\ \text { B. } \mathrm{Al}^{-}(s) \rightarrow \mathrm{Al}^{3+}(a q)+3 e^{-} \text {and } \mathrm{Au}(s) \rightarrow \mathrm{Au}^{+}(a q)+\mathrm{e}^{-} \\ \text {C. } \mathrm{Al}^{3+}(a q)+3 \mathrm{e}^{-} \rightarrow \mathrm{Al}(s) \text { and } \mathrm{Au}(s) \rightarrow \mathrm{Au}^{+}(a q)+\mathrm{e}^{-} \\ \text {D. } \mathrm{Al}^{-}(s) \rightarrow \mathrm{Al}^{3+}(a q)+3 \mathrm{e}^{-} \text {and } \mathrm{Au}^{+}(a q)+\mathrm{e}^{-} \rightarrow \mathrm{Au}(s)\end{array} \]

Which of the following describes a liquid? A. Does not have a fixed volume or a fixed shape B. Has a fixed volume and a fixed shape C. Has a fixed shape but not a fixed volume D. Has a fixed volume but not a fixed shape

Which of the following contains a polar covalent bond? \[ \begin{array}{l}\text { A. } \mathrm{Na}(s) \\ \text { B. } \mathrm{O}_{2} \\ \text { C. } \mathrm{NaCl} \\ \text { D. } \mathrm{NO}\end{array} \]

What is the correct name for \( \mathrm{Na}_{2} \mathrm{O} \) ? \( \begin{array}{l}\text { A. Sodium(II) oxide } \\ \text { B. Disodium oxide } \\ \text { C. Sodium dioxide } \\ \text { D. Sodium oxide }\end{array} \)

What is the net ionic equation for the reaction between \( \mathrm{Na}_{2} \mathrm{SO}_{4} \) and \( \mathrm{CaCl}_{2} \) ? \[ \begin{array}{l}\text { A. } \mathrm{Na}_{2} \mathrm{SO}_{4}(a q)+\mathrm{CaCl}_{2}(a q) \rightarrow \mathrm{CaSO}_{4}(s)+2 \mathrm{NaCl}(a q) \\ \text { B. } 2 \mathrm{Na}^{+}(a q)+\mathrm{SO}_{4}{ }^{2-}(a q)+\mathrm{Ca}^{2+}(a q)+2 \mathrm{Cl}^{-}(a q) \rightarrow \mathrm{CaSO}_{4}(s)+2 \mathrm{Na}^{+}+ \\ 2 \mathrm{Cl}^{-}(a q) \\ \text { C. } \mathrm{SO}_{4}{ }^{2-}(a q)+\mathrm{Ca}^{2+}(a q) \rightarrow \mathrm{CaSO}_{4}(s) \\ \text { D. } 2 \mathrm{Na}^{+}(a q)+2 \mathrm{Cl}^{-}(a q) \rightarrow 2 \mathrm{NaCl}(a q)\end{array} \]

What is characteristic of an ionic bond? A. Electrons move freely among many atoms in a metal. B. Electrons are shared between two different atoms. C. Electrons are lost from one atom and gained by another. D. Electrons are attracted to an atom on another molecule.

Which element is in the same group as Al (aluminum)? \( \begin{array}{l}\text { A. } \mathrm{Si} \text { (silicon) } \\ \text { B. } \mathrm{Mg} \text { (magnesium) } \\ \text { C. B (boron) } \\ \text { D. } \mathrm{Zn} \text { (zinc) }\end{array} \)

What kind of reaction is symbolized by \( A B+C D \rightarrow A D+C B \) ? A. Decomposition B. Synthesis C. Double replacement D. Single replacement