Write the value of 'R' in S.I. system? Write the formula mass of NaCl? Write the bond line formula of hept-2-ene? Balance the nuclear reaction: 11854Xe ightarrow ? + 10n

Here are the answers to the questions:

i) Write the value of 'R' in S.I. system?
The value of the ideal gas constant 'R' in the S.I. system is:

$\boxed{\text{8.314 J mol}^{-1}\text{K}^{-1}}$

ii) Write the formula mass of NaCl?
To calculate the formula mass of NaCl, we sum the atomic masses of Sodium (Na) and Chlorine (Cl).
Atomic mass of Na $\approx 22.99 \, \text{g/mol}$
Atomic mass of Cl $\approx 35.45 \, \text{g/mol}$
Formula mass of NaCl $= 22.99 + 35.45 = 58.44 \, \text{g/mol}$
$\boxed{\text{58.44 g/mol}}$

iii) Write the bond line formula of hept-2-ene?
Hept-2-ene is a hydrocarbon with 7 carbon atoms and a double bond between the second and third carbon atoms.

The bond-line formula is:

      /\
     /  \
    /    \
   /      \
  /        \
 /          \

(A zigzag line with 7 vertices, and a double bond between the second and third vertices from one end).
$\boxed{\text{A 7-carbon chain with a double bond between C2 and C3.}}$

iv) Balance the nuclear reaction: $^{118}_{54}$Xe $\rightarrow$ ? + $^{1}_{0}$n
In a nuclear reaction, both the mass number (superscript) and the atomic number (subscript) must be conserved.
Let the unknown nuclide be $^A_Z\text{X}$.
Conservation of mass number: $118 = A + 1 \implies A = 117$
Conservation of atomic number: $54 = Z + 0 \implies Z = 54$
The element with atomic number 54 is Xenon (Xe).
So the balanced reaction is:

$\boxed{\text{}^{117}_{54}\text{Xe}}$

v) Write the units of equilibrium constant?
The units of the equilibrium constant ($K_c$ or $K_p$) depend on the stoichiometry of the specific chemical reaction. For a general reaction $a\text{A} + b\text{B} \rightleftharpoons c\text{C} + d\text{D}$, the units of $K_c$ would be $(\text{mol/L})^{\Delta n}$, where $\Delta n = (c+d) - (a+b)$. Similarly, for $K_p$, the units would be $(\text{atm})^{\Delta n}$ or $(\text{Pa})^{\Delta n}$. If $\Delta n = 0$, the equilibrium constant is unitless.
$\boxed{\text{Units depend on the stoichiometry of the reaction (e.g., (mol/L)}^{\Delta n}\text{ or (atm)}^{\Delta n}\text{).}}$

vi) Write the name of hydrocarbon that is used as Lubricant?
Paraffin wax (a mixture of long-chain alkanes) or mineral oil (a mixture of liquid hydrocarbons) are common hydrocarbon-based lubricants.
$\boxed{\text{Paraffin wax (or Mineral oil)}}$

vii) Name the type of adsorption in which van der Waals force are present?
The type of adsorption in which van der Waals forces are present is physisorption (physical adsorption).
$\boxed{\text{Physisorption}}$

viii) Write the oxidation number of oxygen in superoxide?
Superoxides contain the superoxide ion, $\text{O}_2^-$.
Let the oxidation number of oxygen be $x$.
Since there are two oxygen atoms and the total charge is -1:

$\boxed{\text{-1/2}}$