A sample of ammonia (NH3) gas is completely decomposed to nitrogen and hydrogen gases over heated iron wool. If the total pressure is 719 mmHg after the reaction, calculate the partial pressures of N2 and H2. Enter your answers in scientific notation.

539.3mmHg of H₂

179.7mmHg of N₂

Explanation:

Ammonia, NH₃, reacts completely producing N₂ and H₂ thus:

2 NH₃ → N₂ + 3H₂

That means there are produced 4 moles of gases and 3 are of H₂ and 1 of N₂

Total pressure (Sum of pressures of N₂ and H₂) is 719mmHg. 3 parts are of H₂ and 1 of H₂

Thus, partial pressures of the products after reaction are:

719mmHg ₓ (3 H₂ / 4) = 539.3mmHg of H₂

719mmHg ₓ (1 N₂ / 4) = 179.7mmHg of N₂

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.