6. Is the following sentence true or false? A chemical equation must be balanced in order to show that mass is conserved during a reaction. 7. Circle the letter of the name given to the numbers that appear before the formulas in a chemical equation. \( \begin{array}{ll}\text { a. subscripts } & \text { b. mass numbers } \\ \text { c. atomic numbers } & \text { d. coefficients }\end{array} \) 8. Is the following sentence true or false? Because the equation \( \mathrm{N}_{2} \mathrm{H}_{4}+\mathrm{O}_{2} \longrightarrow \mathrm{~N}_{2}+\mathrm{H}_{2} \mathrm{O} \) has two nitrogen atoms on each side, the equation is balanced.

Based on bond type, which compound has the highest melting point? 1. \( \mathrm{CH}_{3} \mathrm{OH} \) 2. \( \mathrm{C}_{6} \mathrm{H}_{14} \) 3. \( \mathrm{CaCl}_{2} \) 4. \( \mathrm{CCl}_{4} \)

Questão 2) Qual o valor da variação de entalpia da reação a seguir? \[ C_{(g r \text { fite })}+\mathrm{O}_{2(g)} \rightarrow \mathrm{CO}_{2(g)} \] Dados: \( \mathrm{C}_{(\mathrm{grffte})}+\frac{1}{2} \mathrm{O}_{2(g)} \rightarrow \mathrm{CO}_{(\mathfrak{g})} \quad \Delta H_{1}=-110,3 \mathrm{KJ} \) \( \mathrm{CO}_{(g)}+\frac{1}{2} \mathrm{O}_{2(g)} \rightarrow \mathrm{CO}_{2(g)} \quad \Delta H_{2}=-283,0 \mathrm{KJ} \)

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

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

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