What is the empirical formula of a hydrocarbon that contains 89,94 by mass?
89.94 what (unit) per mass of what(element)?
What is the empirical formula of a hydrocarbon that contains 89,94% by mass?
C'mon Peter. You can't get anywhere by just recopying the problem. You MUST say what the 89.94 is? Is that grams, gallons, percent, earthworms, or WHAT? Second, you MUST say WHAT it is. If it's a hydrocarbon, that means hydrogen and carbon BUT that 89.94 (whatever the unit) is either hydrogen or carbon. You must identify which or you won't get any help from anyone here because your problem is not complete.
Answer: C3H4
So basically what you would do is you world take the 89.94 and divide that by the mass of carbon (and I am just going to round) and that would be 89.94/12=7.495 (I'll round that to 7.5). Then you would subtract 100-89.94 and you're going to subtract by 100 because we are dealing with percent, and percent is ALWAYS out of 100%. So after subtracting you're going to get 10.06 for hydrogen. The mass for hydrogen is 1, so then you'll divide 10.06/1 and the answer is going to be 10.06.
Example: C= 89.94/12 = 7.495----> 7.5
H= 10.06/1 = 10.06 ----> 10.1
You then take the smallest ANSWER you got out of Carbon and Hydrogen. Which is 7.5 from carbon and divide EACH answer.
Example: C= 89.94/12 = 7.495----> 7.5 7.5/7.5 =1
H= 10.06/1 = 10.06 ----> 10.1 10.1/7.5 =1.34---> round to 1.3
Like what one of the previous people stated. You can only round the answer for the empirical formula if its like 3.9 to 4, 5.01 to 5, 2.1 to 2. So, our answer is 1.3 and we can't round it and you can't leave the answer as a decimal.
Example:
Our answer is going to be from 1.3 to 1 1/3 (a mixed fraction).
To get rid of the mixed fraction you're going to multiply 3 (denominator of fraction) from each side.
Example:
(3)1 1/3(3) now the 3 is going to cross out each other from the denominator and you're going to multiply the 3 to the 1 (WHOLE NUMBER of the fraction)
so then, you'll get 3x1= 3, and since the 3 from the denominator of the fraction cancelled out you're only going to get a 1 from the numerator. After, you'll add the number you multiplied and the numerator together.
Example:
product of the 3x1 =3 and what's left of the fraction a.k.a the numerator =1
3+1=4
Since, now we have a whole number 4 will be the answer for hydrogen. H4!
Now, go back to when we had the mixed fraction
1 1/3 and we had to multiply by 3 on each side.
Remember we had to multiply by 3 to cancel out the denominator
The 3 (a.k.a the multiplier) is now going to be your NEW answer for 3.
So the final answer is:
C3H4
*I hope you could understand everything, I know the notes are long, but its hard to type this instead of writing it. I also hope that everything was actually useful and helpful.
Goodluck!
To determine the empirical formula, we need to know the molar masses of the elements present in the hydrocarbon. Since the hydrocarbon consists of only hydrogen (H) and carbon (C), we will calculate the empirical formula based on these two elements.
To find the empirical formula, we follow these steps:
1. Determine the mass of carbon and hydrogen in the compound. We are given that the hydrocarbon contains 89.94% carbon. Let's assume we have 100g of the compound. Therefore, the mass of carbon in this compound is 89.94g.
2. Determine the number of moles for carbon and hydrogen. To find the number of moles, divide the mass of each element by their respective molar masses. The molar mass of carbon (C) is 12.01g/mol, and the molar mass of hydrogen (H) is 1.01g/mol.
Number of moles of carbon = mass of carbon / molar mass of carbon
Number of moles of carbon = 89.94g / 12.01g/mol = 7.49 mol
3. To determine the number of moles of hydrogen, we need to subtract the mass of carbon from the total mass of the compound.
Mass of hydrogen = Total mass of hydrocarbon - Mass of carbon
Mass of hydrogen = 100g - 89.94g = 10.06g
Number of moles of hydrogen = mass of hydrogen / molar mass of hydrogen
Number of moles of hydrogen = 10.06g / 1.01g/mol = 9.96 mol
4. To obtain whole numbers for the empirical formula, we divide the number of moles of each element by the smallest number of moles obtained (in this case, carbon).
Empirical formula = C7.49H9.96
5. Finally, we round the subscripts to the nearest whole number. In this case, we can multiply the entire empirical formula by 4 to obtain whole numbers.
Empirical formula = C30H40
Therefore, the empirical formula of the hydrocarbon that contains 89.94% carbon is C30H40.