Inorganic Chemistry Answers

This contains the name of each element. Fill in the missing blanks with the appropriate nuclear symbol, atomic number, mass number, number of protons, electrons and neutrons of the following elements:

Element Name

Nuclear Symbol

Atomic Number

Mass Number

# of Protons

# of Electrons

# of Neutrons

1.helium

2.potassium

3.boron

4.calcium

5.oxygen

6.silver

7.aluminum

8.sodium

9.tungsten

10.bismuth

 Chemical bonding refers to the formation of a bond between two or more atoms, molecules or ions. Answer the following questions in regard to chemical bond in a chemical compound.

 (a) Draw the Lewis structure and predict the molecular geometry of the following molecules:

i.  NH3 ii.  H2O  iii.  CF4

(b) Using Lewis dot structures, indicate the movement of electrons during the formation of the ionic compound calcium oxide (CaO) from calcium (Ca) and oxygen (O).

(c) Sketch the geometry of the NF3 molecule. Indicate lone pairs of electrons on nitrogen.

 Explain the following statements in accordance to variation in characteristic of atoms in Periodical Table.

 (a) Choose and explain which element has the greater value for following properties: i. electron affinity.

    Na or F. 

ii. electronegativity.

    Cl or Ca.        

iii. ionization energy.

    S or Se.

iv. atomic radius.

    C or Sn.

v. metallic property.

    Si or Br. 

By referring to the chemical equation given, calculate the volume of nitrogen gas in litres, required to react with 40.0 g of magnesium at a pressure of 2.25 atm and a temperature of 15 °C.

            3Mg (s) + N₂ → Mg₃N₂ (s)

A nitrogen gas container has a volume of 35.0 L. Calculate the mass of nitrogen in the container if the gas has a pressure of 1800 torr at 42°C

Lead metal is obtained from lead sulfide through the following reaction:

          2PbS(s) + 2C(s) + 3O₂(g) → 2Pb(s) +2CO(g) + 2SO₂(g)

 (a)If 100g of PbS is reacted with excess C and O_2, calculate the mass of lead metal obtained.  ( 5 )

 (b)Suppose 100 g of PbS is reacted with 4g of C and 20g O₂.

Find the limiting reactant for this reaction.     

  ( 4 )

 (c)For question (b) above, calculate the mass of lead metal obtained.  ( 4 )

 (d)By referring to the question (c) above, If 31.2g Pb is obtained as the yield. Calculate the percentage of yield.  ( 2 )

 (e)Calculate mass of oxygen is needed to produce 500g of lead metal.