Stoichiometry Quiz 5

1 / 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__________?

0.58

1.72

0.5

0.2

2 / 50

Refractory bricks having lower porosity have _______?

Greater strength

Low thermal conductivity

High insulating properties

Low heat capacity

3 / 50

Raoult?s law is obeyed by a ______ solution?

Normal

None of these

Molar

Saturated

4 / 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

5 / 50

Pick out the wrong statement?

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

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

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

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

6 / 50

Pick out the wrong unit conversion ?

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

1 kcal = 3.968 BTU = 0.00116 kWh = 0.00156 hp

1 Joule = 4.186 calorie

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

7 / 50

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

Silica

None of these

Superduty fireclay

Chromite

8 / 50

Pick out the wrong unit conversion of calorific value?

1 BTU/lb = 2.3 kcal/kg

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

1 kcal/m3 = 0.1124 BTU/ft3

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

9 / 50

Solutions which distil without change in composition are called_________?

Azeotropic

Saturated

Supersaturated

Ideal

10 / 50

Pick out the wrong unit conversion ?

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

1 mm Hg = 1 torr = 133.3 Pa

1 kPa = 100 bar

None of these

11 / 50

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

Beryllia

Carborundum

Thoria

Corundum

12 / 50

Solutions having the same osmotic pressure are called ______ solutions?

Saturated

Isotonic

Ideal

Dilute

13 / 50

S.T.P. corresponds to __________?

760 torr & 0?C

760 mm Hg gauge pressure & 15.5?C

1 atm. absolute pressure & 15.5?C

101.325 kPa gauge pressure & 15.5?C

14 / 50

Pick out the wrong statement?

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

All A., B., and C.

The value of Cp at critical temperature and pressure reaches infinity

15 / 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.

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

Sizes of the component molecules are approximately equal

16 / 50

Pick out the wrong statement?

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

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

Both B. and C.

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

17 / 50

Silica bricks are never used for lining the__________?

By-product coke ovens

Dome of blast furnace stoves

Beehive coke ovens

Roof of open hearth furnace

18 / 50

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

1630-1670

> 2000

> 1730

1520-1630

19 / 50

Pick out the wrong unit conversion of temperature?

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

?R = 273 + ?F

?F = (?C + 17.778) ? 1.8

?C = (F- 32) ? 0.555

20 / 50

Pick out the wrong statement ?

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

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

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

Most of the hydrocarbons are non-polar

21 / 50

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

Yield enhancement

Heat conservation

Product enrichment

None of these

22 / 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

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

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

23 / 50

Size range of the colloids particles is ___________?

50 ? 200 microns

500 ? 1000 microns

10 ? 50 Angstrom

5 ? 200 milli-microns

24 / 50

Pick out the wrong statement?

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

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

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

25 / 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

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

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

26 / 50

Pick out the wrong statement?

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

Refractories used in muffle furnace should have low thermal conductivity

The electrical resistivity of refractories drops rapidly with rise in temperature

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

27 / 50

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

Total pressure

Neither A. nor B.

Both A. and B.

Vapor pressure at dry bulb temperature

28 / 50

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

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

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

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

29 / 50

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

Slag attack

Fusion under load

CO attack

Thermal spalling

30 / 50

Pick out the wrong statement?

Calcined magnesite is also called dead burnt magnesite

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

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

31 / 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?

Doubling

Fourfold increase

No change

1/4th reduction

32 / 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

33 / 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_________?

m/s

mole/m2.s.Pa

cm/s

k.mole/m2.s.Pa

34 / 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/inch = 1.488 kcal/m2. hr.?C/m

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

35 / 50

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

Lowers

Either A. or B.; depends on its quantity

Increases

Does not affect

36 / 50

Pick out the wrong statement?

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

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

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

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

37 / 50

Real gases approach ideal behaviour at_____?

Low pressure & high temperature

High pressure & low temperature

High pressure & high temperature

Low pressure & low temperature

38 / 50

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

Bisulphite

Chloride

Carbonate (monohydrate)

Thiosulphate

39 / 50

Quartz is___________?

Stable form of silica upto 870?C

Transformed to Cristobalite on heating above 1470?C

Converted to Tridymite on firing between 870 to 1470?C

All A., B. and C.

40 / 50

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

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

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

41 / 50

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

Coke ovens

Insulation

Regenerators

Muffle furnaces

42 / 50

Pick out the wrong statement?

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

43 / 50

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

1 tonne = 1000 kg = 22.046 lbs

None of these

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

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

44 / 50

Pick out the wrong statement ?

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

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

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

None of these

45 / 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__________?

xB.Patm

(Patm ? Pvw)xB

PvB

xB.PvB

46 / 50

Recycling in a chemical process facilitates_____?

All A., B. & C.

Heat conservation

Enrichment of product

Increased yield

47 / 50

Pick out the wrong unit conversion of heat transfer rate?

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

1 kcal/hr= 1.163 Watt

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

1 Watt = 1.163 kcal/hr

48 / 50

Refractory bricks with lower permeability is produced by using __________?

Finer grog size

All A., B. and C.

Higher firing temperature

Higher moulding pressure

49 / 50

Raoult?s law is not applicable to the_____?

Both B. & C.

Concentrated solutions

Solutes which dissociate or associate in the particular solution

Solutions containing non-volatile solute

50 / 50

Pick out the wrong statement?

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

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

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

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

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