3. Identifica, a partir del número atómico \( (Z) \) los elementos químicos. \( \begin{array}{l}\text { a) }(Z=82): \\ (Z=17): \\ (Z=24): \\ (Z=78): \\ \text { ( } Z=33): \\ \text { c) } \\ \text { f) }(Z=44):\end{array} \)

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

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

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. Aluminum reacts with oxygen according to the following reaction: \[ 4 \mathrm{Al}(s)+3 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{Al}_{2} \mathrm{O}_{3}(s) \] How many liters of oxygen gas at STP are required to completely react with 55.0 g of aluminum?

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.