if 8.99g of scandium and 8.99g of oxygen react to give scandium oxide and a leftover of oxygen 3.65g. what percentage of scandium oxide is the oxygen

You used 8.99 - 3.65 = 5.34 g O2 for 8.99 g of Sc

5.34 + 8.99 = 14.33 g total Sc2O3

5.34 / 14.33 = .373 or 37.3 %
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check
O3 = 3 * 16 = 48
Sc2 = 2 * 45 = 90
total molecular mass = 138
48/138 = .347 or 34.7 %
looks like the experiment was a little off :)

To find the percentage of oxygen in scandium oxide, we can first calculate the total mass of scandium oxide produced:

Mass of scandium = 8.99 g
Mass of oxygen = 8.99 g - 3.65 g (leftover) = 5.34 g

To form scandium oxide, we need 1 atom of scandium (Sc) and 2 atoms of oxygen (O2). The molar mass of Sc is 44.96 g/mol, and the molar mass of O2 is 32.00 g/mol.

Using this information, we can calculate the moles of scandium and oxygen:

Moles of scandium = Mass of scandium / Molar mass of scandium
Moles of scandium = 8.99 g / 44.96 g/mol = 0.200 mol

Moles of oxygen = Mass of oxygen / Molar mass of oxygen
Moles of oxygen = 5.34 g / 32.00 g/mol = 0.167 mol

Since scandium forms Sc2O3 with 2 moles of oxygen, we can calculate the moles of Sc2O3 formed:

Moles of Sc2O3 = (2 * Moles of oxygen) = 2 * 0.167 mol = 0.334 mol

Now, we can find the mass of Sc2O3 using its molar mass, which is 137.87 g/mol:

Mass of Sc2O3 = Moles of Sc2O3 * Molar mass of Sc2O3
Mass of Sc2O3 = 0.334 mol * 137.87 g/mol = 46.09 g

Finally, we can calculate the percentage of oxygen in Sc2O3:

Percentage of oxygen = (Mass of oxygen / Mass of Sc2O3) * 100
Percentage of oxygen = (5.34 g / 46.09 g) * 100 = 11.57%

Therefore, the percentage of oxygen in the scandium oxide is approximately 11.57%.

To find the percentage of oxygen in scandium oxide, we need to determine the total mass of scandium oxide and the mass of oxygen in it.

First, let's calculate the total mass of scandium oxide by adding the masses of scandium and oxygen:
Mass of scandium = 8.99g
Mass of oxygen = 3.65g
Total mass of scandium oxide = mass of scandium + mass of oxygen
Total mass of scandium oxide = 8.99g + 3.65g = 12.64g

Now, let's determine the mass of oxygen in scandium oxide by subtracting the leftover oxygen mass from the total mass of oxygen:
Mass of oxygen in scandium oxide = Total mass of oxygen - leftover oxygen mass
Mass of oxygen in scandium oxide = 3.65g - 3.65g = 0g

Finally, to find the percentage of oxygen in scandium oxide, we divide the mass of oxygen in scandium oxide by the total mass of scandium oxide, and then multiply by 100:
Percentage of oxygen in scandium oxide = (Mass of oxygen in scandium oxide / Total mass of scandium oxide) x 100
Percentage of oxygen in scandium oxide = (0g / 12.64g) x 100
Percentage of oxygen in scandium oxide = 0 x 100
Percentage of oxygen in scandium oxide = 0%

Therefore, the percentage of oxygen in scandium oxide is 0%.