Question

The specific heat of water is 4.18 j/(g⋅∘c). calculate the molar heat capacity of water. express your answer to three significant figures and include the appropriate units.

Answer 1

Explanation:

It is known that relation between specific heat and molar heat capacity is as follows.

             Molar specific heat = Specific heat × Molar mass

It is given that specific heat of water is 4.18 $J/g^{o}C$. Now, we will calculate the molar mass water as follows.

      Molar mass of oxygen = 15.99 g/mol

      Molar mass of $H_{2}$ = $(2 \times 1.00)$ g/mol = 2.00 g.mol

Hence, molar mass of $H_{2}O$ = (15.99 + 2.00) g/mol

                                                    = 17.99 g/mol

Therefore, calculate the molar specific heat of water as follows.

              Molar specific heat = Specific heat × Molar mass

                                               = $4.18 J/g^{o}C \times 17.99 g/mol$

                                               = 75.2 $J/mol^{o}C$    

Thus, we can conclude that the molar heat capacity of water is 75.2 $Jmol^{o}C$.

Answer 2

Specific heat capacity of any substance comes with the unit : J/(g*degree C)
for molar capacity , change gram -> moles  unit ( J / moles * degree C)

4.18 J  / mol - degree C

H = 1.01 g * 2 =   2.02 g
O = 16 g

2.02 + 16  =  18.02  g

Now  :-    4.18  J / mol- degree C) *  18.02 /  1 mole H2O
molar heat  =  75.3 J / mol - degree C



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