2. Circle the letter of each equation that represents a synthesis reaction. a. \( 2 \mathrm{Na}+\mathrm{Cl}_{2} \longrightarrow 2 \mathrm{NaCl} \) b. \( 2 \mathrm{NaCl} \longrightarrow 2 \mathrm{Na}+\mathrm{Cl}_{2} \) c. \( 2 \mathrm{H}_{2} \mathrm{O} \longrightarrow 2 \mathrm{H}_{2}+\mathrm{O}_{2} \) d. \( 2 \mathrm{H}_{2}+\mathrm{O}_{2} \longrightarrow 2 \mathrm{H}_{2} \mathrm{O} \) 3. Is the following sentence true or false? A decomposition reaction is the opposite of a synthesis reaction. 4. Write the equation for the decomposition of calcium carbonate into calcium oxid and carbon dioxide. 5. Circle the letter of the correct answer. Copper reacts with silver nitrate in a single-replacement reaction. What are the products of this reaction? a. copper(II) nitride and silver oxide b. copper(II) nitrate and silver c. copper(II) oxide and silver nitrate d. copper, nitrogen, and silver oxide

Questão 1) São dadas as seguintes equações termoquímicas: \( \begin{array}{l}\text { I) } \mathrm{C}_{(\mathrm{s})}+\mathrm{O}_{2(\mathrm{~g})} \longrightarrow \mathrm{CO}_{2(\mathrm{~g})} \quad \Delta \mathrm{H}=-94,1 \mathrm{kcal} / \mathrm{mol} \\ \begin{array}{l}\text { II) } \mathrm{H}_{2(\mathrm{~g})}+1 / 2 \mathrm{O}_{2(\mathrm{~g})}\end{array} \longrightarrow \mathrm{H}_{2} \mathrm{O}_{(\mathrm{l})} \quad \Delta \mathrm{H}=-68,3 \mathrm{kcal} / \mathrm{mol} \\ \text { III) } \mathrm{C}_{(\mathrm{s})}+2 \mathrm{H}_{2(\mathrm{~g})} \longrightarrow \mathrm{CH}_{4(\mathrm{~g})} \quad \Delta \mathrm{H}=-17,9 \mathrm{kcal} / \mathrm{mol} \\ \text { Calcule o calor liberado, em kcal, na reação de combustão de } 1 \text { mol de gás metano. } \\ \mathrm{CH}_{4(\mathrm{~g})}+2 \mathrm{O}_{2(\mathrm{~g})} \longrightarrow \mathrm{CO}_{2(\mathrm{~g})}+2 \mathrm{H}_{2} \mathrm{O}_{(\mathrm{l})} \quad \Delta \mathrm{H}=\text { ? }\end{array} \$ \begin{array}{l}\longrightarrow\end{array} \)

5) \( \mathrm{Ag}_{2} \mathrm{O} \rightarrow \)

5. At what pressure will 7.89 g of ammonia gas, \( \mathrm{NH}_{3} \), occupy 7.46 L at \( 20.0^{\circ} \mathrm{C} \) ?

10 Essay 5 points Please identify the following components for the element Selenium: 1 Chemical Symbol 2. Atomic Number 3. Family \# 4. Valence Electrons 5. Category Edit View Insert Format Tools Table

14 Nitrogen has atomic number 7 and oxygen has atomic number 8 What is total number of electrons in \( \left(\mathrm{NO}_{3}\right)^{-} \)ion ? \( \begin{array}{ll}\text { (a) } 15 \mathrm{e}^{-} & \text {(b) } 31 \mathrm{e}^{-} \\ \text {(c) } 32 \mathrm{e}^{-} & \text {(d) } 46 \mathrm{e}^{-}\end{array} \)