Which element is not a part of a nitrogenous base?\?
1 answer:
You might be interested in
Answer: The empirical formula for the given compound is
Explanation:
The chemical equation for the combustion of compound having carbon and hydrogen follows:
where, 'x' and 'y' are the subscripts of carbon and hydrogen respectively.
We are given:
Mass of
We know that:
Molar mass of carbon dioxide = 44 g/mol
For calculating the mass of carbon:
In 44 g of carbon dioxide, 12 g of carbon is contained.
So, in 22.0 g of carbon dioxide, of carbon will be contained.
For calculating the mass of hydrogen:
Mass of hydrogen = Mass of sample - Mass of carbon
Mass of hydrogen = 7.0 g - 6 g
Mass of hydrogen = 1.0 g
To formulate the empirical formula, we need to follow some steps:
Step 1: Converting the given masses into moles.
Moles of Carbon =
Moles of Hydrogen =
Step 2: Calculating the mole ratio of the given elements.
For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.5 moles.
For Carbon =
For Hydrogen =
Step 3: Taking the mole ratio as their subscripts.
The ratio of Fe : C : H = 1 : 2
Hence, the empirical formula for the given compound is
Answer:
a) The mean repeat unit molar mass for PEVA is 30.72 g/mol
b) degree of polymerization of the copolymer is 1300
Explanation:
Given that;
the wt% of copolymer consist of 12.9 wt% of vinyl acetate and 87.1 wt% Ethylene.
Basis: 100 g of PEVA consist of 12.9 of vinyl acetate and 87.1g of Ethylene.
now we calculate the mole fraction of vinyl acetate Ethylene in the copolymer;
the molecular weights of vinyl acetate and ethylene are 86.09 g/mol and 28.05 g/mol respectively
so
moles of vinyl acetate = wt. of vinyl acetate / molecular weights of vinyl acetate
moles of vinyl acetate = 12.9 g / 86.09 g/mol
moles of vinyl acetate = 0.1498 mol
moles of Ethylene = wt. of Ethylene / molecular weights of Ethylene
moles of Ethylene = 87.1 g / 28.05 d/mol
moles of Ethylene = 3.1052 mol
Total moles = 0.1498 mol + 3.1052 mol = 3.255 mol
Next we calculate the mole percent;
mole percent of vinyl acetate = moles of vinyl acetate / total moles
= (0.1498 mol / 3.255 mol) × 100
= 4.6%
mole percent of Ethylene = moles of Ethylene / total moles
= (3.1052 mol / 3.255 mol) × 100
= 95.397% ≈ 95.4%
we know that, mean repeat unit molar mass for a sample = ∑
where is the fraction ratio and
is the molecular weight
so or the PEVA
mean repeat unit molar mass M = ( ) + (
)
so we substitute
M = ( 4.6% × 86.09) + ( 95.4% × 28.05 )
M = 3.96014 + 26.7597
M = 30.72 g/mol
Therefore, The mean repeat unit molar mass for PEVA is 30.72 g/mol
b)
Degree of polymerization
=
where is the number average molecular weight ( 39,870 g/mol )
so we substitute
= 39,870 g/mol / 30.72 g/mol
= 1297.85 ≈ 1300 { 3 significance figure }
Therefore, degree of polymerization of the copolymer is 1300