There are several ways to visually represent compounds. For this particular organic compound, we can use the skeletal formula and the expanded formula. The skeletal makes use of lines to show which atoms are bonded to each other. The expanded formula shows the species of the atoms and their bonding with other atoms. I have attached the two representations.
Answer : The correct option is, Only Student B
Explanation :
Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.
In the Lewis-dot structure the valance electrons are shown by 'dot'.
The given molecule is, 
As we know that nitrogen has '5' valence electrons and hydrogen has '1' valence electron.
Therefore, the total number of valence electrons in
= 5 + 3(1) = 8
According to Lewis-dot structure, there are 6 number of bonding electrons and 2 number of non-bonding electrons.
The Lewis dot structure of student A is wrong because there is a coordinate bond present between the nitrogen and hydrogen is not covalent.
Thus, the correct Lewis-dot structure of
is shown by the student B.
PH is calculated using <span>Handerson- Hasselbalch equation,
pH = pKa + log [conjugate base] / [acid]
Conjugate Base = Acetate (CH</span>₃COO⁻)
Acid = Acetic acid (CH₃COOH)
So,
pH = pKa + log [acetate] / [acetic acid]
We are having conc. of acid and acetate but missing with pKa,
pKa is calculated as,
pKa = -log Ka
Putting value of Ka,
pKa = -log 1.76 × 10⁻⁵
pKa = 4.75
Now,
Putting all values in eq. 1,
pH = 4.75 + log [0.172] / [0.818]
pH = 4.072
2.10098*10^47 atoms
Because no. Of atoms = no. Of moles * avogadros no
Answer:
The standard heat of formation of Compound X at 25°C is -3095.75 kJ/mol.
Explanation:
Mass of compound X = 7.00 g
Moles of compound X = 
Mass of water in calorimeter ,m= 35.00 kg = 35000 g
Change in temperature of the water in calorimeter = ΔT
ΔT = 2.113°C
Specific heat capacity of water ,c= 4.186 J/g °C
Q = m × c × ΔT

Heat gained by 35 kg of water is equal to the heat released on burning of 0.100 moles of compound X.
Heat of formation of Compound X at 25°C:

= -3095.75 kJ/mol