Question

Determine the number of moles in a 38.2 g sample of sodium chloride (NaCl).

Answer 1

The number of moles in a 38.2 g sample of sodium chloride (NaCl) is calculated as 0.072 mol NaCl. By understanding the dissociation of NaCl, we also find that there are 0.14 mol of ions present in the sample.

Step-by-step explanation:

To determine the number of moles in a 38.2 g sample of sodium chloride (NaCl), we use the following steps:

1. First, we convert from grams to moles of NaCl using the molar mass of NaCl as the unit conversion factor. The molar mass of NaCl is the sum of the atomic masses of sodium (Na) and chlorine (Cl), which is 22.99 amu for Na and 35.45 amu for Cl, giving us a total of 58.44 g/mol for NaCl. Therefore, the number of moles of NaCl is calculated by dividing the mass of the sample by the molar mass.
   
   0.072 mol NaCl
2. Then, to determine the number of moles of ions present in the sample, we consider that each mole of NaCl dissociates into two ions - one sodium ion (Na+) and one chloride ion (Cl-). Since there are two ions for every mole of NaCl, we use the number of moles of NaCl already found and multiply by the ratio of moles of ions per mole of NaCl (2 mol ions/1 mol NaCl) to find the number of moles of ions:
   
   0.14 mol ions

Answer 2

`\huge{ \boxed{0.653 \: moles}}`

Step-by-step explanation:

The number of moles of the NaCl sample can be found by using the formula:

`n = (m)/(M)`

where:

m is the mass in grams

M is the molar mass in g/mol

n is the number of moles

From the question:

m = 38.2 g

Molar mass (M) of NaCl = 23 + 35.5 = 58.5 g/mol

`\therefore \: n = (38.2)/(58.5) \\ = 0.653 \: \: mol`