Compound A consisting of carbon and hydrogen only. The compound was found to contain 80% carbon by mass,cal. its empiri.
assume you have 100grams total
so there is 80 gramsC
and 20gH
lets look at moles
C 80/12=6.666
H 20/1=20
so the mole ratio then is (divide the lessor number into each ...
C 1
H 3
CH3 is the empirical formula
To find the empirical formula of the compound, we need to determine the simplest whole number ratio of the atoms present.
Given that Compound A contains 80% carbon by mass, we can assume that there is 80g of carbon in a 100g sample. Similarly, the remaining 20% or 20g would be hydrogen.
Step 1: Convert the mass of each element to moles using their molar masses.
The molar mass of carbon (C) is approximately 12g/mol, and the molar mass of hydrogen (H) is approximately 1g/mol.
Number of moles of carbon = mass of carbon / molar mass of carbon = 80g / 12g/mol = 6.67 mol
Number of moles of hydrogen = mass of hydrogen / molar mass of hydrogen = 20g / 1g/mol = 20 mol
Step 2: Divide each mole value by the smallest number of moles calculated to obtain a whole number ratio.
Dividing by 6.67 (the smallest number of moles), we get:
Number of moles of carbon = 6.67 mol / 6.67 mol = 1 mol
Number of moles of hydrogen = 20 mol / 6.67 mol =~ 3 mol
Step 3: Determine the empirical formula using the whole number ratio from Step 2.
The empirical formula of Compound A is CH3, as there is one carbon atom and three hydrogen atoms in the simplest whole number ratio.
Therefore, the empirical formula of Compound A is CH3.
To determine the empirical formula of a compound, we need the percent composition by mass of each element in the compound. Given that the compound consists of only carbon and hydrogen and contains 80% carbon by mass, we can assume the remaining 20% is hydrogen.
To simplify the calculation, let's assume we have 100 grams of the compound.
Since the compound is 80% carbon by mass, we have 80 grams of carbon (80% of 100 grams). Similarly, since the compound is 20% hydrogen by mass, we have 20 grams of hydrogen (20% of 100 grams).
Now, we need to convert these masses into moles. To do this, we divide the mass of each element by its molar mass. The molar masses of carbon and hydrogen are approximately 12 g/mol and 1 g/mol, respectively.
For carbon:
moles of carbon = mass of carbon / molar mass of carbon
moles of carbon = 80 g / 12 g/mol
moles of carbon ≈ 6.67 mol
For hydrogen:
moles of hydrogen = mass of hydrogen / molar mass of hydrogen
moles of hydrogen = 20 g / 1 g/mol
moles of hydrogen = 20 mol
The ratio of moles of carbon to moles of hydrogen is approximately 6.67:20. To simplify this ratio, we divide both sides by the smallest number of moles (6.67):
moles of carbon / moles of hydrogen ≈ 6.67 / 6.67 : 20 / 6.67
moles of carbon / moles of hydrogen ≈ 1 : 3
So, the empirical formula of Compound A is CH3.