Assuming a basis of 100 g of Kevlar, therefore the masses
are:
C = 70.6 g
H = 4.2 g
N = 11.8 g
O = 13.4 g
We know the molar masses are:
C = 12.01, H = 1.008, N = 14.01, O = 16.00
Calculating for the moles per element:
C = 70.6 / 12.01 = 5.88 mol
H = 4.2 / 1.008 = 4.17 mol
N = 11.8 / 14.01 = 0.84 mol
O = 13.4 / 16 = 0.84 mol
To get the empirical formula, the next step is to divide
everything by the smallest moles = 0.84. So:
C = 7
H = 5
N = 1
O = 1
Hence the empirical formula is:
C7H5NO
<span>Quantum mechanic model is based on mathematics. As per this theory the exact position and momentum of electron is impossible to understand. It uses complex shapes of orbitals called electron clouds. n describes the energy of an electron. Larger the value of n larger the distance of electron from the nucleus and larger the orbital. l describles the shape of orbital. Orbitals having same of value of n and different values for l are called subshells.</span>
First, we will get the average pH of the two given values:
average pH = (6.4+8) / (2) = 7.2
At this average pH, the concentration of the acid from the phenol red is equal to the concentration of the base.
pH = 7.2
[H+] = 10^(-7.2) = 6.3 * 10^-8
Phenol red has the general formula HA, this gives us:
HA <.......> H+ + A-
At pH = 7.2, [H+] = [A-]
<span>Ka = [H+][A-]/ [HA]
</span>Ka = [H+] = <span>6.3 x 10^-8</span>
Why do molecules combined into chains?
