Density

Q. Henry's law constant for $C{O}_2$ in water is
$1.67\times {10}^{8}Pa\text{at}298K$. Calculate the quantity of $C{O}_2\text{in}500mL$ of soda water when packed under $2.5atmC{O}_2$ pressure at $298K$.

Q. Calculate:

$A$: Molality of $KI$ if the density of $20\%\left(\text{mass/mass}\right)$ aqueous $KI$ is $1.202gm{L}^{-1}$.

$B$: Molarity of $KI$ if the density of $20\%\left(\text{mass/mass}\right)$ aqueous $KI$ is $1.202gm{L}^{-1}$.

$C$: Mole Fraction of $KI$ if the density of $20\%\left(\text{mass/mass}\right)$ aqueous $KI$ is $1.202gm{L}^{-1}$.

Q. The number of octahedral void(s) per atom present in a cubic-close-packed structure is: (1) 2 (2) 4 (3) 1 (4) 3

Q.

Gold crystallizes in CCP structure. The total number of voids present In $197\mathrm{gms}$ of Gold will be

Q. Iron exhibits bcc structure at room temperature. Above 900°C, it transforms to fcc structure. The ratio of density of iron at room temperature to that at 900°C (assuming molar mass and atomic radii of iron remains constant with temperature) is:

1. $\frac{3\left(\sqrt{3}\right)}{4\left(\sqrt{2}\right)}$
2. $\frac{4\left(\sqrt{3}\right)}{3\left(\sqrt{2}\right)}$
3. $\frac{\left(\sqrt{3}\right)}{\left(\sqrt{2}\right)}$
4. $\frac{1}{2}$

Q.

An element (atomic mass 100 g/mol) having bcc structure has a unit cell edge of 400 pm. Then the density of the element is

1. 10.376 g/cm³
2. 7.289 g/cm³
3. 2.144 g/cm³
4. 5.188 g/cm³

Q.

A metal has a fcc lattice. The edge length of the cell is 404 pm. The density of the metal is $2.72gc{m}^{-3}$ . The molar mass of the metal is
($N_A$ Avogadro's constant = $6.02\times {10}^{23}mo{l}^{-1}$)

1. $20gmo{l}^{-1}$

2. $40gmo{l}^{-1}$

3. $30gmo{l}^{-1}$

4. $27gmo{l}^{-1}$

Q. The correct order of melting point of 3d transition metals is

1. $Ti<V<Cr<Mn<Fe<Cu$
2. $Ti<V<Cr>Mn<Fe<Cu$
3. $Ti<V<Cr>Mn<Fe>Cu$
4. $Ti<V>Cr<Mn<Fe>Cu$

Q. A solution containing 10.2g glycerine per litre is isotonic with a 2 percent solution of glucose. What is the molecular mass of glycerine?

Q. $200c{m}^3$ of an aqueous solution of a protein contains $1.26g$ of the protein. The osmotic pressure of such a solution at $300K$ is found to be $2.57\times {10}^{-3}bar$. Calculate the molar mass of the protein.

Q.

A metal crystallizes into two cubic phases, FCC and BCC whose unit cell lengths are 3.5 and 3.0 Å respectively. The ratio of densities of FCC and BCC.

1. 
   

2. 

3. 
   

4. 
   

Q.

Silver crystallizes in fcc lattice. If the edge length of the cell is $4.07\times {10}^{-8}cm$ and density is $10.5gc{m}^{-3}$, calculate the atomic mass of silver.

Q.

An element with a molar mass of $2.7\times {10}^{-2}$ $\mathrm{kg}{\mathrm{mol}}^{-1}$ forms a cubic unit cell with an edge length of $405pm$. If its density is $2.7\times {10}^3$ $\mathrm{kg}{\mathrm{m}}^{-3}$, the radius of the element is approximately ______ ${10}^{-12}\mathrm{m}$ (to the nearest integer).

Q.

Copper crystallises into a fcc lattice with edge length $3.61\times {10}^{-8}cm.$ Show that the calculated density is in agreement with its measured value of $8.92gc{m}^{-3}$

Q.

Mole fraction of urea in 900 gram water is 0.05. Density of Solution is 1.2 g/cm³. Find molarity of Solution.

Q. A metal crystallises with a F.C.C. lattice. The edge of the unit cell is 408 pm. The diameter of the metal atom is

1. 144 pm
2. 204 pm
3. 288 pm
4. 408 pm

Q.

Lithium borohydride crystallizes in an orthorhombic system with 4 molecules per unit cell. The unit cell dimensions are a = 6.8Å, b = 4.4Å and C = 7.2Å. If the molar mass is 21.76g. Density of crystal is (gm/cm³)

1. 0.67

2. 0.44

3. 0.23

4. 0.096

Q.

The unit cell of aluminum is a cube with an edge length of 405 pm. The density of aluminum is $2.70gc{m}^{-3}$. What is the structure of the unit cell of aluminum?

1. Body-centered cubic cell

2. Face-centered cubic cell

3. End-centered cubic cell

4. simple cubic cell

Q. At ${25}^{\circ }C$ and $760mm$ of $Hg$ pressure a gas occupies $600mL$ volume. What will be its pressure at a height where temperature is ${10}^{\circ }C$ and volume of the gas is $640mL.$

Q. A swimmer coming out from a pool is covered with a film of water weighing about $18g.$ How much heat must be supplied to evaporate this water at $298K?$ Calculate the internal energy of vaporization at $298K.{△}_{vap}{H}^{\ominus }$ for water at $298K=44.01kJmo{l}^{-1}$

Q. A crystalline solid of a pure substance has a face-centred cubic structure with a cell edge of 400 pm. If the density of the substance in the crystal is $8gc{m}^{-3},$ then the number of atoms present in 256 g of the crystal is $N\times {10}^{24}$. The value of N is

Q.

Explain how much portions of an atom located at (i) corner and (ii) body centre of a cubic unit cell is part of its neighbouring unit cell.

Q.

Calculate the weight of CO₂ which occupies a volume of 11.2 dm³ at STP.

Q. When heated above ${916}^{\circ }C$, iron changes its BCC crystalline form to FCC without the change in the radius of atom. The ratio of density of the crystal before heating and after heating is (Given : $\sqrt{3}=1.73and\sqrt{2}=1.41$):

1. $1.069$
2. $1.231$
3. $0.725$
4. $0.917$

Q. In the face-centred cubic lattice structure of gold the closest distance between gold atoms is: ('a' being the edge length of the cubic unit cell)

1. $\frac{a}{\sqrt{2}}$
2. $\frac{a}{2\sqrt{2}}$
3. $2\sqrt{2}$
4. $a\sqrt{2}$

Q. What type of defect can arise when a solid is heated?

Q.

A compound XY crystallizes in BCC lattice with a unit cell edge length of 480 pm. If the radius of Y⁻ is 225 pm. What will be the radius of X⁺

1. $225\mathrm{pm}$

2. $255\mathrm{pm}$

3. $127.5\mathrm{pm}$

4. $190.68\mathrm{pm}$

Q. 6 : 6 coordination number of $NaCl$ changes to 8 : 8 coordination on:

1. applying high pressure
2. increase in temperature
3. both (A) and (B)
4. no effect on coordination

Q. calculate the number of formula units of a crystal AB, having Cscl type structure in 240 gm.The unit cell edge lengthof AB is 200 pm and density of crystal is 6gm/cc.

Q.

How is the relative vapor density of a gas related to the relative molecular mass of the gas?