A sample of an oxide of antimony (Sb) contained 51.5 g of antimony combined with 16.9 g of oxygen. What is the simplest formula for the oxide?
51.5 g of Sb*(1 mole/121.76 g)= moles of Sb=0.418
16.9 g of O * (1 mole/16.0 g)= moles of O=1.06
divide lowest moles by the other
Sb=0.418/0.418=1
O=1.06/0.418=2.52
2.52 *2 to get a whole number
Sb2O5
I could be wrong though.
Thank you Mr. Devron! I learnt something from you as well. The compound is Antimony Pentoxide, and I did indeed not realize that after dividing by the lowest moles you can multiply!
hey i got Sb2O5
for the oxide is O5 right?
Sb2O5 is correct. As for multiplying by whole numbers; remember that you can round to whole numbers as long as you don't round too much. That is, 8.1 can usually and safely be rounded to 8.0 or 8.9 to 9.0 but rounding 2.5 to 3 or 2 isn't done for 2.5 can be multiplied by whole numbers to get a whole number. Numbers like 2.25, 2.33, 2.5, 2.67, 2.75 usually aren't rounded but multiplied by whole numbers to obtain whole numbers; i.e., 2.33 x 3 = 6.99 which then rounds to 7.0
To determine the simplest formula for the oxide of antimony, we need to find the ratio of antimony to oxygen in the compound.
Step 1: Find the moles of antimony and oxygen
- The molar mass of antimony (Sb) is 121.76 g/mol.
- The molar mass of oxygen (O) is 16.00 g/mol.
Moles of antimony = Mass of antimony / Molar mass of antimony
Moles of antimony = 51.5 g / 121.76 g/mol
Moles of antimony = 0.4231 mol
Moles of oxygen = Mass of oxygen / Molar mass of oxygen
Moles of oxygen = 16.9 g / 16.00 g/mol
Moles of oxygen = 1.0563 mol
Step 2: Find the ratio of antimony to oxygen
Now, we need to find the simplest whole number ratio of the moles of antimony to oxygen. Divide both moles by the smallest value to get the simplest ratio.
Simplest ratio = Moles of antimony / Moles of oxygen
Simplest ratio = 0.4231 mol / 0.4231 mol = 1
Simplest ratio = 1 / 1.0563 = 0.9472 (approximately)
Since the ratio is not close to a whole number, we can multiply by a whole number to get close to whole numbers. Let's multiply by 4 to eliminate decimals:
Multiplied ratio = Simplest ratio * 4
Multiplied ratio = 0.9472 * 4 = 3.7888
Now, round the multiplied ratio to the nearest whole number:
Rounded ratio = round(Multiplied ratio)
Rounded ratio = round(3.7888)
Rounded ratio = 4
Step 3: Write the empirical formula
The empirical formula represents the simplest whole number ratio of atoms in a compound. In this case, the empirical formula for the oxide of antimony is:
Sb4O4
You need to know the molar ratio for Antimony Oxide! Since Sb has an oxidation of +3 and Oxygen has a oxidation of -2, you need two Sb atoms and three O atoms.
Sb2O3
Figure out how many moles you have of antimony and oxygen..
51.5 g Sb * 1 mol/ 121.76 g= 0.43 moles Sb
16.9 g O * 1 mol/ 16 g= 1.06 moles O
I don't think even in the simplest form, the masses of the elements given are sufficient for a stable compound of Sb2O3.