obviously something but not known what!
We can't tell. What's the other 90 percent? If you meant 40/60 instead... the mass of sulfur is twice that of oxygen, so a mass ratio of 40:60 is equivalent to an atom ratio of 1:3. The empirical formula would be SO3.
You cannot without information on the densities of the two substances.
It is around 21/2 %, by weight.
The weight will depend on how much of the substance there is.
Mol% or weight%? Weight percent seems more likely; let's assume that and see what we come up with. We'll assume 100g of the substance to make the numbers pretty; in that case we have: * 34.9 g Na / 23.0 g/mol Na = 1.52 mol Na * 16.4 g B / 10.8 g/mol B = 1.52 mol B (so far the weight percent is looking like a good assumption) * 48.6 g O / 16.0 g/mol O = 3.04 mol O (looking like a greatassumption) Converting that to small whole number ratios, we get an Na:B:O ratio of 1:1:2, so the empirical formula is NaBO2.
Oxygen comprises about 47% by weight of Earth's crust
12
Oxygen
This element is oxygen.
Oxygen!ElementAbundancepercent by weightAbundanceparts per million by weightOxygen46.1%461,000Silicon28.2%282,000Aluminum8.23%82,300Iron5.63%56,300Calcium4.15%41,500Sodium2.36%23,600Magnesium2.33%23,300Potassium2.09%20,900Titanium0.565%5,650Hydrogen0.14%1,400
Oxygen
Oxygen
Oxygen
it is 77
This element is oxygen.
KH2PO4 contains 28.67 % potassium.
Atomic percent is based on the number of atoms in a sample. So if the sample has x number of oxygen atoms and x number of iron atoms it would report 50% oxygen and 50% iron (atomic percent). Weight percent is based on the mass of the elements detected. So if we used the above example and reported the results as weight percent we would get 22.3% oxygen and 77.7% iron. Weight percent takes into consideration the mass or atomic weight of the elements and not just the number of atoms. Most people use weight percent although for chemistry atomic percent may be more useful.