Determine the atomic weight in grams per mole of sodium carbonate, [tex]Na_2CO_3[/tex]. The atomic weights for the elements are [tex]Na = 23 \, g/mol[/tex], [tex]C = 12 \, g/mol[/tex], and [tex]O = 16 \, g/mol[/tex].

A. [tex]1.134 \, g/mol[/tex]
B. [tex]2.51 \, g/mol[/tex]
C. [tex]113 \, g/mol[/tex]



Answer :

Let's calculate the molecular weight of sodium carbonate ([tex]\(\text{Na}_2\text{CO}_3\)[/tex]) step-by-step.

1. Identify the atomic weights of each element:
- Sodium (Na): 23 g/mol
- Carbon (C): 12 g/mol
- Oxygen (O): 16 g/mol

2. Determine the number of each type of atom in the compound:
- There are 2 sodium (Na) atoms.
- There is 1 carbon (C) atom.
- There are 3 oxygen (O) atoms.

3. Calculate the total contribution to the molecular weight from each type of atom:
- Sodium: [tex]\(2 \times 23 \, \text{g/mol} = 46 \, \text{g/mol}\)[/tex]
- Carbon: [tex]\(1 \times 12 \, \text{g/mol} = 12 \, \text{g/mol}\)[/tex]
- Oxygen: [tex]\(3 \times 16 \, \text{g/mol} = 48 \, \text{g/mol}\)[/tex]

4. Add all these contributions together to find the total molecular weight:
[tex]\[ 46 \, \text{g/mol} + 12 \, \text{g/mol} + 48 \, \text{g/mol} = 106 \, \text{g/mol} \][/tex]

So, the atomic weight of sodium carbonate ([tex]\(\text{Na}_2\text{CO}_3\)[/tex]) is [tex]\(106 \, \text{g/mol}\)[/tex].

Given the options provided:

1. [tex]\(1.134 \, \text{g/mol}\)[/tex]
2. [tex]\(2.51 \, \text{g/mol}\)[/tex]
3. [tex]\(113 \, \text{g/mol}\)[/tex]

The closest (and accurate) answer given is:
3. [tex]\(113 \, \text{g/mol}\)[/tex]

Even though the exact calculation yields 106 g/mol, the closest option provided is 113 g/mol, given the constraints of the problem.