The combustion of ammonia in the presence of excess oxygenyields no2(g) and h2o(g): 4nh3(g) + 7o2(g) → 4no2(g) + 6h2o(g)the combustion of 43.9 mg of ammonia produces how many grams ofno2(g)? a. 178b. 0.119c. 43.9d. 0.954e. 2.58

There will be produced 0.119 grams of NO2 (option B)

Explanation:

Step 1: Data given

Mass of ammonia = 43.9 mg

Oxygen is in excess

Molar mass of NH3 = 17.03 g/mol

Step 2: The balanced equation

4NH3(g) + 7O2(g) → 4NO2(g) + 6H2O(g)

Step 3: Calculate moles NH3

Moles NH3 = Mass NH3 / molar mass NH3

Moles NH3 = 0.0439 g/ 17.03 g/mol

Moles NH3 = 0.00258 moles

Step 4: Calculate moles of NO2

For 4 moles NH3 we need 7 moles of O2 to produce 4 moles NO2 and 6 moles of H2O

For 0.00258 moles of NH3 we'll have 0.00258 moles of NO2

Step 5: Calculate mass of NO2

Mass of NO2 = moles NO2 * molar mas NO2

Mass NO2= 0.00258 moles * 46 g/mol

Mass NO2 = 0.119 grams

There will be produced 0.119 grams of NO2 (option B)

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.