11. In an endothermic reaction, heat from the surroundings plus the chemical energy of the reactants is converted into the of the products. Circle the correct answer. a. kinetic energy b. potential energy c. chemical energy

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 ? \( \begin{array}{ll}\text { (a) } 15 \mathrm{e}^{-} & \text {(b) } 31 \mathrm{e}^{-} \\ \text {(c) } 32 \mathrm{e}^{-} & \text {(d) } 46 \mathrm{e}^{-}\end{array} \)

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

6. If 380 g of cottonseed oil measures 415 mL , what is its specific gravity? 7. If \( 2 \mathrm{fl} \). oz. of glycerol weighs 74.1 g , what is its specific gravity? 8. Five pints of diluted hydrochloric acid weights 2.79 kg . Calculate its specific gravity.

Consider the same reaction as in question 6 above: \[ 4 \mathrm{Al}(s)+3 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{Al}_{2} \mathrm{O}_{3}(s) \] How many grams of aluminum oxide will be produced from the complete reaction of 1.27 L of oxygen gas at 783.0 mmHg and \( 30.0^{\circ} \mathrm{C} \) ?