Stoichiometry Quiz 5

1 / 50

Pick out the wrong statement?

The average value of heat of neutralisation of dilute solutions of weak acids and bases is much less compared to that for strong acids and bases

The standard heat of solution of the hydrate of a substance is the difference between the heat of solution of the anhydrous substance and its heat of hydration

The accompanying enthalpy change, when a solute is dissolved in solvent, depends upon the nature & amount of the solute & the solvent, on the temperature & on the initial & final concentrations of the solution

The integral heat of solution of either component cannot be calculated from heat of mixing data

2 / 50

Pick out the wrong statement?

The value of Cp at critical temperature and pressure reaches infinity

All A., B., and C.

The effect of pressure on heat capacity of gases at pressure above one atmosphere and above the critical temperature is negligible

The value of Cp of gases increases with increase in pressure, above atmospheric pressure

3 / 50

Refractoriness/fusion points of ?Superduty? refractories is ______ ?C?

> 1730

1630-1670

> 2000

1520-1630

4 / 50

Silica bricks are never used for lining the__________?

Dome of blast furnace stoves

Beehive coke ovens

Roof of open hearth furnace

By-product coke ovens

5 / 50

Quartz is___________?

Converted to Tridymite on firing between 870 to 1470?C

Transformed to Cristobalite on heating above 1470?C

All A., B. and C.

Stable form of silica upto 870?C

6 / 50

Pick out the wrong conversion formula for the conversion of weight units ?

None of these

1 ton = 2240 lbs = 1016 kg = 1.016 tonnes = 1.12 U.S. tons

1 tonne = 1000 kg = 22.046 lbs

1 U.S. ton = 907 kg = 0.907 tonne = 0.893 ton

7 / 50

Pick out the wrong statement?

A gas bubble at a pressure of Pg is passed through a solvent with a saturation vapour pressure of Ps. If the time of passage of the bubble is long and air is insoluble in the solvent, the mole fraction of solvent in the bubble will be equal to Ps/Pg

To make 100 kg of a solution containing 40% salt by mixing solution A (containing 25% salt) and solution B (containing 50% salt), the amount of solution A required is 40 kg

1.2 gm atoms of carbon and 1.5 gm moles of oxygen are reacted to give 1 gm mole of carbon dioxide. The limiting reactant is carbon. The percent excess reactant supplied is 25

A supersaturated solution of a sparingly soluble solute, at a concentration of C, is being fed to a crystalliser at a volumetric flow rate of V. The solubility .of the solute is C1. The output rate of solids from an efficient crystalliser is (C + C1) V

8 / 50

Pick out the wrong statement?

Generally, the heat capacities of compounds are lower in the liquid than in the solid state

The heat capacity of a heterogeneous mixture is an additive property, but when solutions are formed, this additive property may no longer exist

Atomic heat capacities of all solid elements decrease greatly with decrease in temperature, approaching a value of zero at absolute zero temperature, when in the crystalline state

Atomic heat capacities of the crystalline solid elements are nearly constant and equal to 6.2 kcal/kg-atom according to the law of Petit and Dulong

9 / 50

Pick out the wrong unit conversion of thermal conductivity ?

1 W/cm.?C = 85.985 kcal/m.hr.?C = 57.779 BTU/ft.hr.?F

1 BTU/ft2.hr.?F/ft = 1.488 kcal/m2. hr.?C/m

1 kcal/m.hr.?C = 0.672 BTU/ft.hr.?F = 1.163 W/m. ?K

1 BTU/ft2.hr.?F/inch = 1.488 kcal/m2. hr.?C/m

10 / 50

Solutions which distil without change in composition are called_________?

Supersaturated

Saturated

Azeotropic

Ideal

11 / 50

Pick out the wrong unit conversion of heat transfer co-efficient?

1 W/m2.?C = 0.1761 BTU/ft2.hr.?F.

1 BTU/ft2.hr.?F = 4.88 kcal/m2.hr.?C = 20.44 kJ/m2.hr?C = 5.678 W/m2.?C

1 kcal/m2.hr.?K = 1.163 W/m2.?C

1 kcal/m2.hr.?C = 0.2048 BTU/ft2.hr. ?F. = 1.163 W/m2.?K

12 / 50

Sodium _______ has inverted solubility curve i.e. its solubility increases with the lowering of temperature?

Bisulphite

Thiosulphate

Carbonate (monohydrate)

Chloride

13 / 50

Pick out the wrong unit conversion of temperature?

?R = 273 + ?F

Temperature difference of 1?K = 1?C = 9/5?F

?C = (F- 32) ? 0.555

?F = (?C + 17.778) ? 1.8

14 / 50

Pick out the wrong unit conversion of heat transfer rate?

1 kcal/hr= 1.163 Watt

1 Watt = 1.163 kcal/hr

1 BTU/ft2.hr = 2.712 kcal/m2.hr

1 kcal/m2.hr = 0.3687 BTU/ft2.hr = 1.163 Watt/m2

15 / 50

Size range of the colloids particles is ___________?

500 ? 1000 microns

5 ? 200 milli-microns

10 ? 50 Angstrom

50 ? 200 microns

16 / 50

Pick out the wrong statement?

Refractoriness under load (RUL) of a refractory is always less than its refractoriness

For reducing spalling tendency, the refractory should be well fired and its porosity should be more

The electrical resistivity of refractories drops rapidly with rise in temperature

Refractories used in muffle furnace should have low thermal conductivity

17 / 50

Pure aniline is evaporating through a stagnant air film of 1 mm thickness at 300 K and a total pressure of 100 KPa. The vapor pressure of aniline at 300 K is 0.1 KPa. The total molar concentration under these conditions is 40.1 mole/m3. The diffusivity of aniline in air is 0.74 ? 10-5m2/s. The numerical value of mass transfer co-efficient is 7.4 ? 10-3. Its units are_________?

mole/m2.s.Pa

m/s

cm/s

k.mole/m2.s.Pa

18 / 50

Pick out the wrong unit conversion ?

1 ppm = 1 ml/m3 = 1 mg/kg

1 stoke = 1 m2/second

1 Pascal second = 10 poise

1 kgf= 9.8 Newton

19 / 50

Refractories used in/for _______ should have low thermal conductivity?

Insulation

Coke ovens

Regenerators

Muffle furnaces

20 / 50

Pure oxide refractories are generally monocrystalline in nature and are self bonded _______ bricks are generally used as moderator in nuclear reactors?

Carborundum

Beryllia

Corundum

Thoria

21 / 50

Simultaneous doubling of the absolute temperature of a gas and reduction of its pressure to half will result in ______ in the volume of the gas?

1/4th reduction

Doubling

No change

Fourfold increase

22 / 50

Pick out the wrong statement?

Superduty fireclay bricks correspond to a pyrometric cone equivalent of 26-28

Calcined magnesite is also called dead burnt magnesite

Graphite refractories are also called plumbago refractories

Insulating refractories used in place of regular refractory bricks are usually called light weight refractories, and they have similar composition as heavy bricks

23 / 50

Pick out the wrong statement?

The binary mixture of a particular composition in both vapor and liquid state is known as an azeotropic mixture

Total number of molecules contained in 22.4 litres of hydrogen at NTP is 6.023 x 1023

Heat capacity of a diatomic gas is higher than that of a monatomic gas

Equal volumes of Argon and Krypton contain equal number of atoms

24 / 50

Solutions having the same osmotic pressure are called ______ solutions?

Saturated

Ideal

Dilute

Isotonic

25 / 50

Recycling in a chemical process facilitates_____?

Enrichment of product

Increased yield

All A., B. & C.

Heat conservation

26 / 50

Pick out the wrong statement ?

None of these

?Reduced temperature? of a substance is the ratio of its existing temperature to its critical temperature, both expressed on Celsius scale

?Reduced volume? is the ratio of the existing molal volume of a substance to its critical molal volume

?Reduced pressure? is the ratio of the existing pressure of a substance to its critical pressure

27 / 50

Real gases approach ideal behaviour at_____?

High pressure & high temperature

Low pressure & low temperature

High pressure & low temperature

Low pressure & high temperature

28 / 50

S.T.P. corresponds to __________?

1 atm. absolute pressure & 15.5?C

101.325 kPa gauge pressure & 15.5?C

760 mm Hg gauge pressure & 15.5?C

760 torr & 0?C

29 / 50

Raoult?s law is obeyed by a ______ solution?

Molar

None of these

Normal

Saturated

30 / 50

Pick out the wrong statement about the recycle stream in a process ?

Recycling in a process does not help in getting higher extent of reaction

The ratio of the quantity of a reactant present in the reactor feed of a recycling operation to the quantity of the same reactant entering the process as fresh feed is called combined feed ratio

Recycling in a process stream helps in utilising the valuable reactants to the maximum with minimum loss of reactants

Recycling is exemplified by refluxing back a part of the distillate to the distillation column to maintain the quantity of liquid within the column

31 / 50

Saturated solution of benzene in water is in equilibrium with a mixture of air and vapours of benzene and water at room temperature and pressure. Mole fraction of benzene in liquid is xB and the vapour pressures of benzene and water at these conditions are pv B and pv w respectively. The partial pressure of benzene in air-vapour mixture is__________?

PvB

(Patm ? Pvw)xB

xB.Patm

xB.PvB

32 / 50

Refractory bricks having lower porosity have _______?

Low heat capacity

Greater strength

Low thermal conductivity

High insulating properties

33 / 50

Pick out the wrong unit conversion ?

1 kcal = 3.968 BTU = 0.00116 kWh = 0.00156 hp

1 ft.lbf= 0.3238 calorie = 0.1383 kg.m = 1.356 J = 1.356 N.m

1 ton of TNT (tri-nitro-toluene) = 4.2 GJ (1G = 109)

1 Joule = 4.186 calorie

34 / 50

Raoult?s law states that ?the equilibrium vapor pressure that is exerted by a component in a solution is proportional to the mole fraction of that component?. This generalisation is based on the assumption that the_________?

Attractive forces between like and unlike molecules are approximately equal

All A., B. & C.

Sizes of the component molecules are approximately equal

Component molecules are non-polar and no chemical combination or molecular association between unlike molecules takes place in the formation of the solution

35 / 50

Refractory bricks with lower permeability is produced by using __________?

Higher moulding pressure

Finer grog size

Higher firing temperature

All A., B. and C.

36 / 50

Refluxing of part of the distillate in a fractionating column is a ?recycling operation?, aimed primarily at________?

Product enrichment

Yield enhancement

Heat conservation

None of these

37 / 50

Pick out the wrong unit conversion ?

None of these

1 mm Hg = 1 torr = 133.3 Pa

1 kPa = 100 bar

1 atm. = 760 mm Hg = 29.92 inch Hg = 14.7 psi = 1.013 bar = 1.013 kgf/cm2

38 / 50

Raoult?s law is not applicable to the_____?

Solutions containing non-volatile solute

Solutes which dissociate or associate in the particular solution

Both B. & C.

Concentrated solutions

39 / 50

Pick out the wrong statement ?

Raoult?s law holds good for the solubility of polar gases in non-polar liquids

Most of the hydrocarbons are non-polar

Molecules with symmetrical arrangement (e.g., CH4 and CCl4) are non-polar

Generally, non-polar compounds are chemically inactive, conduct electricity poorly and do not ionise

40 / 50

Pick out the wrong statement?

When equal weights of oxygen and methane are mixed in an empty reactor at room temperature, then the fraction of total pressure exerted by the oxygen is 1/2

One kg mole of an ideal gas at N.T.P occupies 22400 Nm3

Volume occupied by 9.034 x 1023 atoms of oxygen in ozone (O3) at NTP will be 11200 c.c

Ten times dilution of a normal solution (N) reduces its normality to N/10

41 / 50

Pick out the wrong unit conversion of calorific value?

1 BTU/lb = 2.3 kcal/kg

1 kcal/kg = 1.8 BTU/lb = 4.186 kJ/kg

1 kcal/m3 = 0.1124 BTU/ft3

1 BTU/ft3 = 8.9 kcal/m3 = 0.038 MJ/m3

42 / 50

Pick out the wrong unit conversion of mass transfer co-efficient?

1 lb/hr.ft2 = 4.8823 kg/hr.m2

1 kg/hr.m2 = 4.8823 lb/hr.ft2

1 kg/hr.m2.atm= 0.98687 kg/hr. m .bar

1 lb/hr.ft3.atm. = 4.8182 kg/hr.m2.bar

43 / 50

Pick out the wrong statement?

The temperature at which a vapor is saturated is termed as the boiling point

A vapor whose partial pressure is less than its equilibrium vapor pressure, is termed as a ?superheated vapor?

The difference between the existing temperature of a vapor and its saturation temperature (i.e.dew point) is called its ?degree of superheat?

A vapor is termed as a saturated vapor, if its partial pressure equals its equilibrium vapor pressure

44 / 50

Presence of MgO in alumino-silicate refractories _______ its refractoriness ?

Increases

Does not affect

Lowers

Either A. or B.; depends on its quantity

45 / 50

Saturated molal absolute humidity of the vapor-gas mixture depends upon the________?

Neither A. nor B.

Both A. and B.

Total pressure

Vapor pressure at dry bulb temperature

46 / 50

Roof of a basic electric furnace is made of _______ bricks?

Chromite

Superduty fireclay

Silica

None of these

47 / 50

Pick out the wrong statement?

Both B. and C.

Both the freezing point as well as boiling point of sea water is more than that of distilled water

The solution containing equal masses of two liquids ?X? and ?Y? has the same mole fraction of? ?X? and ?Y?

The evaporation of aqueous solution of glucose causes its molarity to increase

48 / 50

Refractories subjected to alternate cycles of heating & cooling are liable to loose their resistance to___________?

Slag attack

CO attack

Fusion under load

Thermal spalling

49 / 50

Pure oxygen is mixed with air to produce an enriched air containing 50 volume % of oxygen. The ratio of moles of air to oxygen used is__________?

1.72

0.58

0.2

0.5

50 / 50

Pick out the wrong statement?

Clausius-Clapeyron equation relates the latent heat of vaporisation to the slope of the vapor pressure curve

Clapeyron equation is given by dP/dT = (?/T) (VG ? VL); where, P = vapor pressure, T = absolute temperature, ? = latent heat of vaporisation, VG and VL = volumes of gas and liquid respectively

Percentage saturation and relative saturation are numerically equal for an unsaturated vapor gas mixture

At the boiling point of liquid at the prevailing total pressure, saturated absolute humidity is infinite

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