como se conforma un atom

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?

How many \( \mathrm{mg} / \mathrm{ml} \) does a \( 2.5 \% \) solution contain?

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

How many moles of carbon dioxide, collected over water, occupy 125 mL at 732.0 mmHg and \( 23.0^{\circ} \mathrm{C} \) ? (water vapor pressure at \( 23.0^{\circ} \mathrm{C}=21.1 \mathrm{mmHg} \) ) \( (0.00481 \mathrm{~mol}) \)

How many mg in each ml of a \( 10 \% \) solution of NaCl ?