Download App

Thermodynamics — Chemistry STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 ScienceChemistryThermodynamics3 Marks
Question
Give the appropriate reason.
  1. It is preferable to determine the change in enthalpy rather than the change in internal energy.
  2. It is necessary to define the 'standard state'.
  3. It is necessary to specify the phases of the reactants and products in a thermochemical equation.
✓

Answer

  1. Because it is easier to make measurement under constant pressure than under constant volume conditions.
  2. Enthalpy change depends upon the conditions in which a reaction is carried out. For making the comparison of results obtained by different people meaningful, the reaction conditions must be well-defined.
  3. Because enthalpy depends upon the phase of reactants and products.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from Thermodynamics→Thermodynamics — all question types→Chemistry STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

Similar questions

Which of the following are isoelectronic species i.e., those having the same number of electrons?
$\text{Na}^+,\text{K}^+,\text{Mg}^{2+},\text{Ca}^{2+},\text{S}^{2-},\text{Ar}.$
→
When electromagnetic radiation of wavelength 300nm falls on the surface of sodium, electrons are emitted with a kinetic energy of 1.68 ×105J mol-1. What is the minimum energy needed to remove an electron from sodium? What is the maximum wavelength that will cause a photo-electron to be emitted?
(h = 6.626 × 10-34Js)
→
Complete the following reactions:
  1. $\text{CH}_3-\text{CH}=\text{CH}_2+\text{HBr}\xrightarrow{\text{Peroxide}}?$
  2. $\text{CH}_3-\text{Cl}+\text{Na}\xrightarrow{\text{Dry ether}}?$
  3. $\text{CH}_3-\text{CH}-\text{CH}_2-\text{CH}_3\xrightarrow[\Delta]{\text{alc. KOH}}\\ \ \ \ \ \ \ \ \ \ \ \ \ \ |\\ \ \ \ \ \ \ \ \ \ \ \ \ \text{Cl}$
→
1. The fact that the enthalpy is a state function forms the basis of a very useful law. Name the law.
2. Two liters of an ideal gas at a pressure of 10 atm expands isothermally at $25^{\circ} C$ into a vacuum until its total volume is 10 liters. How much heat is absorbed and how much work is done in the expansion?
3. A sample of 1.0 mole of a monoatomic ideal gas is taken through a cyclic process of expansion and compression as shown in the figure. What will be the value of $\Delta H$ for the cycle as a whole?
Image
→
Calculate the hydrogen ion concentration in the following biological fluids whose oH are given below :
(a) Human muscle fluid, 6.83
(b) Human stomach fluid, 1.2
(c) Human blood, 7.38
(d) Human saliva, 6.4.
→
What is meant by hybridisation? Compound CH2 = C = CH2 contains sp or sp2 hybridised carbon atoms. Will it be a planar molecule?
→
Correct the following electronic configuration of the elements in the ground state.
  1. $1\text{s}^2\ 2\text{s}^1,2\text{p}^2_\text{x},2\text{p}^2_\text{y},2\text{p}^2_\text{z},3\text{s}62,2\text{p}^1_\text{x}$
  2. $1\text{s}^2\ 2\text{s}^1,2\text{p}^1_\text{x},2\text{p}^1_\text{y},2\text{p}^1_\text{z}$
  3. $1\text{s}^2\ 2\text{s}^1,2\text{p}^6,3\text{s}^2,3\text{p}^6,3\text{d}^5$
  4. $1\text{s}^2\ 2\text{s}^2,2\text{p}^6,3\text{p}^6,3\text{d}^4,4\text{s}^2$
→
If two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element, are in whole number ratio.
  1. Is this statement true?
  2. If yes, according to which law?
  3. Give one example related to this law.
→
Write the molecular orbital electronic configurations of the following species:
  1. $\text{N}_2$
  2. $\text{N}^+_2$
  3. $\text{N}^-_\text{2}$
  4. $\text{N}^{2-}_2$
  1. Calculate their bond orders. ​​​​​​
  2. Predict their magnetic behaviour.
  3. Which of these shows highest para-magnetism?
→
Explain the following:
  1. Common ion effect.
  2. Bronsted Lowry concepts of acids and bases.
→