Assertion (A): The temperature at
Question: Assertion (A): The temperature at which vapour pressure of a liquid is equal to the external pressure is called boiling temperature. Reason (R): At high altitude atmospheric pressure is high. (i) Both A and R are true and R is the correct explanation of A. (ii) Both A and R are true but R is not the correct explanation of A. (iii) A is true but R is false. (iv) A is false but R is true. Solution: Option (iii) is correct....
Read More →Assertion (A): At constant temperature,
Question: Assertion (A): At constant temperature, pV vs V plot for real gases is not a straight line. Reason (R): At high pressure, all gases have Z 1 but at intermediate pressure most gases have Z 1. (i) Both A and R are true and R is the correct explanation of A. (ii) Both A and R are true but R is not the correct explanation of A. (iii) A is true but R is false. (iv) A is false but R is true. Solution: Option (ii) is correct....
Read More →Assertion (A): Three states of matter are the result of a balance between
Question: Assertion (A): Three states of matter are the result of a balance between intermolecular forces and thermal energy of the molecules. Reason (R): Intermolecular forces tend to keep the molecules together but thermal energy of molecules tends to keep them apart. (i) Both A and R are true and R is the correct explanation of A. (ii) Both A and R are true but R is not the correct explanation of A. (iii) A is true but R is false. (iv) A is false but R is true. Solution: Option (i)Both A and ...
Read More →Match the following gas laws with
Question: Match the following gas laws with the equation representing them. Solution: (i) is e (ii) is d (iii) is b (iv) is a...
Read More →Solve this
Question: Show that A(1, -2), B(3, 6), C(5, 10) and D(3, 2) are the vertices of a parallelogram. Solution: Given: Vertices of the quadrilateral are $A(1,-2), B(3,6), C(5,10)$ and $D(3,2)$. Note: For a quadrilateral to be a parallelogram opposite sides of the quadrilateral must be equal in length, and the diagonals must not be equal. $A B=\sqrt{(3-1)^{2}+(6+2)^{2}}=\sqrt{4+64}$ $=2 \sqrt{1} 7$ units $B C=\sqrt{(5-3)^{2}+(10-6)^{2}}=\sqrt{4+16}$ $=2 \sqrt{5}$ units $C D=\sqrt{(3-5)^{2}+(2-10)^{2}}...
Read More →Match the graphs between the
Question: Match the graphs between the following variables with their names : Solution: (i) is c (ii) is a (iii) is d...
Read More →Show that the following set of curves intersect orthogonally:
Question: Show that the following set of curves intersect orthogonally: $y=x^{3}$ and $6 y=7-x^{2}$ Solution: Given: Curves $y=x^{3} \ldots(1)$ $\ 6 y=7-x^{2} \ldots(2)$ Solving (1) \ (2), we get $\Rightarrow 6 y=7-x^{2}$ $\Rightarrow 6\left(x^{3}\right)=7-x^{2}$ $\Rightarrow 6 x^{3}+x^{2}-7=0$ Since $f(x)=6 x^{3}+x^{2}-7$ we have to find $f(x)=0$, so that $x$ is a factor of $f(x)$. when $x=1$ $f(1)=6(1)^{3}+(1)^{2}-7$ $f(1)=6+1-7$ $f(1)=0$ Hence, $x=1$ is a factor of $f(x)$. Substituting $x=1$ ...
Read More →Explain the effect of increasing
Question: Explain the effect of increasing the temperature of a liquid, on intermolecular forces operating between its particles, what will happen to the viscosity of a liquid if its temperature is increased? Solution: As the temperature increases, the intermolecular force operating between its particle decreases, the bond strength increases and also the kinetic energy increases. Hence, as the temperature increases viscosity decreases because the viscosity decreases when the intermolecular force...
Read More →The viscosity of a liquid arises due to strong
Question: The viscosity of a liquid arises due to strong intermolecular forces existing between the molecules. Stronger the intermolecular forces, greater is the viscosity. Name the intermolecular forces existing in the following liquids and arrange them in the increasing order of their viscosities. Also, give a reason for the assigned order in one line. Water, hexane (CH3CH2CH2CH2CH2CH3), glycerine (CH2 OH CH(OH) CH2 OH) Solution: Water has hydrogen bonding existing as intermolecular forces, he...
Read More →Name two phenomena that can
Question: Name two phenomena that can be explained on the basis of surface tension. Solution: 1. Bubbles are round due to surface tension. 2. A needle can float in water is because of surface tension present on the surface of the water....
Read More →he relation between the pressure exerted by an ideal gas
Question: he relation between the pressure exerted by an ideal gas (Pideal) and observed pressure (Pearl) is given by the equation: Pideal = Preal+ an2/V2 If the pressure is taken in Nm-2, the number of moles in mol and volume in m3, Calculate the unit of a. What will be the unit of a when pressure is in atmosphere and volume in dm3? Solution: We know Pideal = Preal+ an2/V2 Pedal Preal= an2/V2 Nm-2 = a*mol2/m6 A = Nm4mol-2 The unit of a when the pressure is taken in Nm-2, number of moles in mol ...
Read More →For real gases the relation between p,
Question: For real gases the relation between p, V and T are given by van der Waals equation: P + an2(V nb) / V2= nRT Wherea and b are van der Waals constants, nb is approximately equal to the total volume of the molecules of a gas. a is the measure of the magnitude of intermolecular attraction. (i) Arrange the following gases in the increasing order of b. Give reason. O2, CO2, H2, He (ii) Arrange the following gases in the decreasing order of magnitude of a. Give reason. CH4, O2, H2 Solution: (...
Read More →Solve this
Question: Show that A(3, 2), B(0, 5), C(-3, 2) and D(0, -1) are the vertices of a square. Solution: Given: The points are $A(3,2), B(0,5), C(-3,2)$ and $D(0,-1)$. Note: For a quadrilateral to be a square, all the sides of the quadrilateral must be equal in length and the diagonals must be equal in length as well. $A B=\sqrt{(0-3)^{2}+(5-2)^{2}}=\sqrt{9+9}$ $=3 \sqrt{2}$ units $B C=\sqrt{(-3-0)^{2}+(2-5)^{2}}=\sqrt{9+9}$ $=3 \sqrt{2}$ units $D A=\sqrt{(3-0)^{2}+(2+1)^{2}}=\sqrt{9+9}$ $=3 \sqrt{2}...
Read More →The critical temperature (T c)
Question: The critical temperature (T c) and critical pressure (Pc) of CO2 are 30.98C and 73atm respectively. Can CO2(g) be liquefied at 32C and 80atm pressure? Solution: CO2 gas cannot be liquefied at a temperature which is greater than its critical temperature i.e 30.98C even by applying any pressure. So as the given temperature is 32C by applying a pressure of 80atm the CO2 gas cannot be liquefied....
Read More →Compressibility factor, Z,
Question: Compressibility factor, Z, of a gas is given as Z = PV/ nRT (i) What is the value of Z for an ideal gas? (ii) For real gas what will be the effect on the value of Z above Boyles temperature? Solution: (i) Compressibility factor, Z is defined as the ratio of the product of pressure and volume to the product of the number of moles, gas constant and temperature. For an ideal gas, the value of Z is 1. (ii) Above Boyles temperature, PV is greater than nRT for real gases so, the value of Z w...
Read More →One of the assumptions of the kinetic
Question: One of the assumptions of the kinetic theory of gases is that there is no force of attraction between the molecules of a gas. State and explain the evidence that shows that the assumption is not applicable for real gases. Solution: Under low pressure and at high temperature the assumption made by kinetic theory is true. At high temperature, the molecules will be very far from each other and at low pressure, the volume of molecule become negligible so they dont interact and hence the as...
Read More →Name two intermolecular forces
Question: Name two intermolecular forces that exist between HF molecules in a liquid state. Solution: Hydrogen bonding and dipole-dipole interaction exist between HF molecule in a liquid state....
Read More →Name the energy which arises due to the motion
Question: Name the energy which arises due to the motion of atoms or molecules in a body. How is this energy affected when the temperature is increased? Solution: Thermal energy arises due to the motion of atoms or molecules in the body. If we increase the temperature then the kinetic energy of atom and molecule increases significantly....
Read More →Show that the points A
Question: Show that the points A(2, -2), B(8, 4), C(5, 7) and D(-1, 1) are the angular points of a rectangle. Solution: Given: The 4 points are A(2, -2), B(8, 4), C(5, 7) and D(-1, 1). Note: For a quadrilateral to be a rectangle, the opposite sides of the quadrilateral must be equal and the diagonals must be equal as well. $A B=\sqrt{36+36}$ $=6 \sqrt{2}$ units $\ldots . .(1)$ $B C=\sqrt{9+9}$ $=3 \sqrt{2}$ units $\ldots(2)$ $C D=\sqrt{36+36}$ $=6 \sqrt{2}$ units ......(3) $A D=\sqrt{9+9}$ ........
Read More →The pressure exerted by saturated
Question: The pressure exerted by saturated water vapour is called aqueous tension. What correction term will you apply to the total pressure to obtain a pressure of dry gas? Solution: The total pressure of the gas is Pmoist gas = Pdry gas By applying the correction term, Pdry gas = Pmoist gas Aqueous tension Therefore, the correction term applied to the total pressure of the gas to get the pressure of dry gas is P moist gas aqueous tension...
Read More →Find the angle to intersection of the following curves :
Question: Find the angle to intersection of the following curves : $y=4-x^{2}$ and $y=x^{2}$ Solution: Given: Curves $y=4-x^{2} \ldots(1)$ $\ y=x^{2} \ldots(2)$ Solving $(1) \(2)$, we get $\Rightarrow y=4-x^{2}$ $\Rightarrow x^{2}=4-x^{2}$ $\Rightarrow 2 x^{2}=4$ $\Rightarrow x^{2}=2$ $\Rightarrow x=\pm \sqrt{2}$ Substituting $\sqrt{2}$ in $y=x^{2}$, we get $y=(\sqrt{2})^{2}$ $y=2$ The point of intersection of two curves are $(\sqrt{2}, 2) \(-\sqrt{2},-2)$ First curve $y=4-x^{2}$ Differentiating...
Read More →The magnitude of the surface tension of liquid depends
Question: The magnitude of the surface tension of liquid depends on the attractive forces between the molecules. Arrange the following in increasing order of surface tension: Water, alcohol (C2H5OH) and hexane [CH3(CH2)4CH3)]. Solution: H-bonding is stronger in water than alcohol, so water has strong intermolecular attraction than alcohol. Increasing order of surface tension is Hexane alcohol water....
Read More →One of the assumptions of the kinetic theory
Question: One of the assumptions of the kinetic theory of gases states that there is no force of attraction between the molecules of a gas. How far is this statement correct? Is it possible to liquefy an ideal gas? Explain. Solution: The above statement is valid. At high-temperature gas, molecules movement become faster such that there is no intermolecular attraction. Under this condition, gas behave like an ideal gas. It is impossible to liquefy an ideal gas since ideal gas has no force of attr...
Read More →Value of universal gas constant (R)
Question: Value of universal gas constant (R) is the same for all gases. What is its physical significance? Solution: The dimensions of the universal gas constant R are energy per degree per mole. In the metre-kilogram-second system, the value of R is 8.3144598 joules per Kelvin per mole. Hence R only depends on the unit of different parameter P, V, n, T. So R values the same for all gases....
Read More →Two different gases ‘A’ and ‘B’ are filled in separate containers
Question: Two different gases A and B are filled in separate containers of equal capacity under the same conditions of temperature and pressure. On increasing the pressure slightly the gas A liquefies but gas B does not liquefy even on applying high pressure until it is cooled. Explain this phenomenon. Solution: The critical temperature is the term used for this phenomenon. Here gas A liquefies means that A is below its critical temperature and gas B does not liquefy on applying high pressure as...
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