Question

Write the names of the following compounds and deduce their molecular masses.$N{a_2}S{O_4},{K_2}C{O_3},C{O_2},NaOH,MgC{l_2},AlP{O_4},NaHC{O_3}$

Answer 1

Hint- We will first write the names of each compound and then find out the molecular masses of the compounds. The formula that will be used for doing all this is given below-
Formula used: Molecular mass=$n$(atomic mass of the element) [where n stands for the number of atoms of that element]

Complete answer:

$N{a_2}S{O_4}$: Sodium Sulphate
Steps for finding the molecular mass are given below-
Molecular mass of $N{a_2}S{O_4}$ = 2(Atomic mass of $Na$) + 1(Atomic mass of $S$) + 4(Atomic mass of $O$)
Molecular Mass -
 $
   \Rightarrow 2 \times \left( {23} \right) + 1 \times \left( {32} \right) + 4 \times \left( {16} \right) \\
    \\
   \Rightarrow 46 + 32 + 64 \\
    \\
   \Rightarrow 142g/mol \\
$
\[{K_2}C{O_3}\]: Potassium Carbonate
Molecular mass-
Molecular mass of \[{K_2}C{O_3}\]= 2$ \times $ (Atomic mass of $K$) + 1$ \times $(Atomic mass of $C$) + 3$ \times $ (Atomic mass of $O$)
Molecular Mass-
$
   \Rightarrow 2 \times \left( {39} \right) + 1 \times \left( {12} \right) + 3 \times \left( {16} \right) \\
    \\
   \Rightarrow 78 + 12 + 48 \\
    \\
   \Rightarrow 138g/mol \\
$
$C{O_2}$: Carbon dioxide
Molecular mass of $C{O_2}$ = 1×$ \times $(Atomic mass of $C$) + 2$ \times $ (Atomic mass of $O$)
Molecular Mass-
$
   \Rightarrow 1 \times \left( {12} \right) + 2 \times \left( {16} \right) \\
    \\
   \Rightarrow 12 + 32 \\
    \\
   \Rightarrow 44g/mol \\
$
$NaOH$: Sodium Hydroxide
Molecular mass of $NaOH$= 1$ \times $(Atomic mass of $Na$) + 1$ \times $(Atomic mass of $O$) + 1$ \times $(Atomic mass of $H$)
Molecular Mass-
$
   \Rightarrow 1 \times \left( {23} \right) + 1 \times \left( {16} \right) + 1 \times \left( 1 \right) \\
    \\
   \Rightarrow 23 + 16 + 1 \\
    \\
   \Rightarrow 40g/mol \\
$
$MgC{l_2}$: Magnesium Chloride
Molecular mass of $MgC{l_2}$= 1$ \times $(Atomic mass of Mg) + 2$ \times $(Atomic mass of Cl)
Molecular Mass-
 $
   \Rightarrow 1 \times \left( {24} \right) + 2 \times \left( {35.5} \right) \\
    \\
   \Rightarrow 24 + 70 \\
    \\
   \Rightarrow 94g/mol \\
$
$AlP{O_4}$: Aluminium Phosphate
Molecular mass of $AlP{O_4}$= 1× (Atomic mass of Al) + 1× (Atomic mass of P) + 4× (Atomic mass of O)
Molecular Mass-
 $
   \Rightarrow 1 \times \left( {27} \right) + 1 \times \left( {31} \right) + 4 \times \left( {16} \right) \\
    \\
   \Rightarrow 27 + 31 + 64 \\
    \\
   \Rightarrow 122g/mol \\
$
$NaHC{O_3}$: Sodium Bicarbonate
Molecular mass of NaHCO3 = 1× (Atomic mass of Na) + 1× (Atomic mass of H) + 1× (Atomic mass of C) + 3× (Atomic mass of O)
Molecular Mass-
$
   \Rightarrow 1 \times \left( {23} \right) + 1 \times \left( 1 \right) + 1 \times \left( {12} \right) + 3 \times \left( {16} \right) \\
    \\
   \Rightarrow 23 + 1 + 12 + 48 \\
    \\
   \Rightarrow 84g/mol \\
$
Hence, we have the solution.
Note: The molecular mass or molecular weight is defined as the total mass of the given compound. It is always equal to the sum of the individual atomic masses of each atom (of the elements) present in the molecule.