A 12 g sample of an unknown compound contains 3.489 g of sodium and 4.870 g of sulfur. The rest is oxygen. Name the compound

Thank you!

3.489 g Na

4.870 g S
12.000-3.489-4.870 = 3.541 g oxygen.

I have rounded the atomic numbers I used below; you should use correct values from the periodic table and that may change the values below slightly.
Convert to moles.
3.487/23 = 0.152
4.87/32 = 0.152
3.541/16 = 0.221

Now we find the ratio of these elements to each other in small whole numbers with the lowest number being 1.000. The easy way to do this is to divide everything by the smallest number.
Na = 0.152/0.152 = 1.00
S = 0.152/0.152 = 1.00
O = 0.221/0.152 = 1.46 and these are not small whole numbers. (It is ok to round SOME but we can't round 1.46 to 1 or 2.) So what can we do. We can multiply everything by a sequence of numbers beginning at 2,3,4,5,6 etc until we get a set of whole numbers. We try the first one (2) and
Na = 1.00 x 2 = 2.00
S = 1.00 x 2 = 2.00
O = 1.46 x 2 = 2.92 which we can round to 3 so the empirical formula is
Na2S2O3. Do you know what that is called? Na2SO4 is sodium sulfate. When an oxygen atom is replaced with a S atom, we call it a thio compound so this one be called sodium ....sulfate. You supply the ....

To find the name of the compound, we need to determine the chemical formula based on the given information.

We have a 12 g sample of the compound containing 3.489 g of sodium and 4.870 g of sulfur. This means that the amount of oxygen in the compound can be found by subtracting the combined mass of sodium and sulfur from the total mass of the compound.

Mass of oxygen = Total mass of compound - (Mass of sodium + Mass of sulfur)

Mass of oxygen = 12 g - (3.489 g + 4.870 g)
Mass of oxygen = 12 g - 8.359 g
Mass of oxygen = 3.641 g

Now we need to find the mole ratio between sodium, sulfur, and oxygen in the compound.

To do this, we divide the mass of each element by their respective atomic masses.

Number of moles of sodium = Mass of sodium / Atomic mass of sodium
Number of moles of sulfur = Mass of sulfur / Atomic mass of sulfur
Number of moles of oxygen = Mass of oxygen / Atomic mass of oxygen

The atomic mass of sodium (Na) is 22.99 g/mol, the atomic mass of sulfur (S) is 32.07 g/mol, and the atomic mass of oxygen (O) is 16.00 g/mol.

Number of moles of sodium = 3.489 g / 22.99 g/mol ≈ 0.152 mol
Number of moles of sulfur = 4.870 g / 32.07 g/mol ≈ 0.152 mol
Number of moles of oxygen = 3.641 g / 16.00 g/mol ≈ 0.227 mol

Now we can determine the simplest whole number ratio between these elements by dividing the number of moles of each element by the smallest number of moles.

Dividing by 0.152 mol (the smallest number of moles), we get:

Sodium: 0.152 mol / 0.152 mol = 1
Sulfur: 0.152 mol / 0.152 mol = 1
Oxygen: 0.227 mol / 0.152 mol ≈ 1.49

Now we need to round these ratios to the nearest whole number.

Sodium: 1 (already a whole number)
Sulfur: 1 (already a whole number)
Oxygen: 1.49 ≈ 1.5 (rounded to the nearest whole number)

The simplest whole-number ratio is NaSO1.5. However, we can't have a non-integer subscript in a chemical formula. So, we multiply the entire formula by 2 to cancel out the decimal in oxygen's subscript.

By doubling the formula, we get Na2SO3 as the chemical formula of the compound.

Based on this formula, the compound is sodium sulfite (Na2SO3).