Ethylene- C2H4 = 85.7% Carbon and 14.3% Hydrogen
Find the atomic masses for each element and multiply it by the number of atoms in the compound, then add.
C- 12.0 * 2= 24.0
H- 1.00 * 4= 4.00
-----------------------
28.0
Take the masses for each element and divide it by the total mass. Then change the answer to get the percent.
C 24.0 / 28.0= .857 = 85.7%
H 4.00 / 28.0= .143 = 14.3%
<h3>
Ethylene is 85.7% Carbon and 14.3% Hydrogen </h3>
Answer : The number of molecules present in nitrogen gas are, 
Explanation :
First we have to calculate the moles of nitrogen gas by using ideal gas equation.
where,
P = Pressure of 
gas = 
(1 atm = 760 mmHg)
V = Volume of gas = 985 mL = 0.982 L (1 L = 1000 mL)
n = number of moles = ?
R = Gas constant = 
T = Temperature of gas = 
Now put all the given values in above equation, we get:
Now we have to calculate the number of molecules present in nitrogen gas.
As we know that 1 mole of substance contains 
number of molecules.
As, 1 mole of gas contains number of molecules
So, 
mole of gas contains 
number of molecules
Therefore, the number of molecules present in nitrogen gas are,
A red super giant hope that helps
Answer:
Model D
Explanation:
Bohr's Model has a planetary look. Where the electrons are in an orbit.
Answer:
b) 3.10
Explanation:
HF ⇄ H
+ + F
Using Henderson-Hasselbalch Equation:
pH = pKa + log [A-]/[HA].
Where;
pKa = Dissociation constant = -log Ka
Hence, pKa of HF = -log 7.2 x 10^-4 = 3.14266
[A-] = concentration of conjugate base after dissociation = moles of base/total volume
= 0.15 x 0.3/0.8
= 0.05625 M
[HA] = concentration of the acid = moles of acid/total volume
= 0.10 x 0.5/0.8
= 0.0625 M
Note: <em>Total volume = 500 + 300 = 800 mL = 0.8 dm3</em>
pH = 3.14266 + log [0.05625/0.0625]
= 3.14267 + (-0.04575749056)
= 3.09691250944
<em>From all the available options below:</em>
<em>a) 2.97
</em>
<em>b) 3.10
</em>
<em>c) 3.19
</em>
<em>d) 3.22
</em>
<em>e) 3.32</em>
The correct option is b.
