Question

NaCl has a Hfus = 30.2 kJ/mol. What is the mass of a sample of NaCl that needs 732.6 kJ of heat to melt completely? 24.3 g 82.7 g 1,407.1 g 1,417.7 g

Answer 1

Hello.

The answer is  1417.7

Its 1417.7 grams becasue you have  to convert the moles to grams.


A mole is the amount of pure substance containing the same number of chemical units as there are atoms in exactly 12 grams of carbon-12 (i.e., 6.023 X 1023).

a coherent, typically large body of matter with no definite shape.

Have a nice day

Answer 2

Answer : The mass of the sample of NaCl will be, 1417.7 grams.

Explanation : Given,

$\Delta H_{fusion}=30.2kJ/mol$

This means that,

As, 1 mole of sample of NaCl has an enthalpy of fusion = 30.2 kJ

And, 1 mole of NaCl has the mass = 58.44 grams

As, 30.2 kJ of heat is needed for a mass 58.44 grams of NaCl

So, 732.6 kJ of heat will be needed for = $\frac{58.44g}{30.2kJ}\times 732.6 kJ=1417.65\approx 1417.7$ grams of NaCl.

Hence, the mass of sample of NaCl will be, 1417.7 grams.