Surface chemistry Questions and Answers

According to Langmuir adsorption isotherm amount of gas adsorb at very high pressure 1 point O Reaches a constant limiting values O Increasing with pressure O Decreasing with pressure Increasing first and decreasing later with pressure

HYSICS CHEMISTRY BIOLOGY English En Consider the following statements i The process of converting a precipitate into colloidal sol is called peptization ii Collodion is a 4 solution of nitro cellulose in a mixture of alcohol and ether iii Clouds are aerosols having small droplets of water suspended in air B C D Only i ii Only i iii Only i ii iii

Function of bleaching powder in the formation of chloroform from ethanol is Only one correct answer A B C To carry out chlorination of acetaldehyde To carry out hydrolysis of chloral Carry out oxidation of ethanol

Consider the following statements i The process of converting a precipitate into colloidal sol is called peptization ii Collodion is a 4 solution of nitro cellulose in a mixture of alcohol and ether iii Clouds are aerosols having small droplets of water suspended in air Choose the correct statement s Only one correct answer A Only ii B C D Only i ii Only i iii Only i ii iii

Q 166 The period of oscillations of a point is Q 166 0 04 sec and the velocity of propagation of oscillation is 300m sec The difference of phases between the oscillations of two points at distances 10m and 16m respectively from the source of oscillations is 2 2 1 2 3 4 after 0 04 sec 300m sec 16m gat 1 2x 3 x 4 N 2 R 10m m tart after

CORRECT statement for leaching is are It is commercially used of ores of Ag Au Al Silver and gold ores are leached out in the form of water soluble complex ions In Bayer s process Fe O3 does not react with leaching reagent Precipitation of Al OH 3 is obtained by adding CO into NaAlO2 solution

vee samajh nahi aaya ke kase electrolyte daalne see aur s uitable solvent daalne se hydrophilic sol coagulate hoogay a Coagulation of lyophilic solsy There are two factors which are responsible for the stability of lyophilic sols These factors are the charge and solvation of the colloidal particles When these two factors are removed a lyophilic sol can be coagulated This is done 1 by adding an electrolyte and ii by adding a suitable solvent When solvents such as alcohol and acetone are added to hydrophilic sols the dehydration of dispersed phase occurs Under this 2344

163 city are 4K 165 155 The root mean square speed of hydrogen molecules of an ideal hydrogen gas kept in a gas chamber is 3180 m s The pressure of the hydrogen gas is Density of hydrogen gas 8 99 x 10 Kg m 1 atmosphere 1 01 x 10 N m 2 1 5 atomsphere 4 3 0 atomsphere 1 1 0 atmosphere 3 2 0 atmosphere HT0171

KN0099 99 A particle starts from rest and move with constant acceleration Its velocity displacement curve 1 2 3 4 www 102 Session KN0100

ALLEN 8 A body starts from rest What is the ratio of the distance travelled by the body during the 4th and 3rd second 1 3 75 73 517 317 37 4 7

ALLEN 81 The energy emitted per second by a black body at 27 C is 10 J If temperature of the black body is increased to 327 C the energy emitted per second will be 1 20 J 2 40 J

1 During adsorption on a solid diatomic molecules of a gas X dissociate into atoms Which of the followin relationships are true for the said process 0 surface coverage on a uniform adsorbent surface ka is th rate constant of adsorption and ka is the rate constant of desorption P is the pressure of gas X A 0 KP 1 KP C K kd B 0 D K KP2 1 KP ka

O A thin liquid film formed between a U shaped wire 7 and a light slider supports a weight of 1 5 x 10 N see figure The length of the slider is 30 cm and its weight negligible The surface tension of the liquid film is 1 0 025 N m 3 0 1 N m Film W 2 0 0125 N m 4 0 05 N m 7

In Freundlich adsorption isotherm slope of AB line is B XE 201 4 log P log n with n 1 n with n 0 1 to 0 5 log with n 1 n 1 n with 0 to 1 n

Which of the following combination leads to formation positive so A 100ml 0 1M KI 100 ml 0 2M AgNO3 B 100 ml 0 1 M HCl 200 ml 0 1 M NaOH C 200 ml and 0 1M KI 100 ml 0 1 M AgNO3 D 50 ml 0 1M KI 100ml 0 1M AgNO3

Which one of the following is not applicable to the phenomenon of spontaneous adsorption A AH O B AG 0 C AS O D AH O 21 For the electrons of oxygen atom which of the following statements is correct A Zef for an electron in a 2s orbital is the same as Zeff for an electron in a 2p 20

70 In Freundlich adsorption isotherm the value of 1 n is a between 0 and 1 in all cases b between 2 and 4 in all cases c always 1 in case of physical adsorption d always 1 in use of chemical adsorption

www android universityupdates in www universityupdates in www ios universitvupdates in Match the following List I www android previousquestionpapers com www previousquestionpapers com www ios previousquestionpapers com A Aerosol B Emulsion C Foam D Gel Type of Colloid S08 JOD 250 Sons A 26365 I A Jos B 55 C 5 D 35 Serox 650 The correct answer is 805 20 A B C D IV V III II B C D I II III IV V List II Phase in medium Solid in solid Liquid in solid Gas in liquid Solid in gas Liquid in liquid arder II SOS I usage Sussargo II 55argos 553argo III 655gos Jabargo IV ago Sunsargo V 555agoe argo

When 1 mol CrCl3 6H2O is treated with excess of AgNO3 3 mole of AgCl are obtained The formula of the complex is Question Type Single Correct Type 1 CrCl3 H O 3 3H2O 2 CrCl H O 4 CI 2H 0 3 CrCl H 0 5 Cl H O

Which of the following is are correct statement about azeotropic mixture Mixture of two liquids Constant boiling mixtures Cannot be separated by fractional distillation All of these

Among the following the surfactant that will from micelles in aqueous solution at the highest molar concentration at ambient conditions CH3 CH 15N CH3 3Br CH3 CH 11OSO3 Na CH3 CH 6COONa CH3 CH 11N CH3 3Br

Select the set having correct statements pertaining to the adsorption of a gas on a solid surface A Physisorption may transform into chemisorptions at high temperature B Chemisorption is more exothermic than physisorption however it is very slow due to higher energy of activation C Adsorption is always exothermic D Physisorption increases with increasing temperature but chemisorptions decreases with increasing temperature 1 A B 2 B C 3 A B C 4 A B D

A substance forms Zwitter ion It can have functional groups A B C NHCOOH NH SOH both A and B

An oven with a radiant heater for drying painted metal parts on a moving conveyor belt is designed as shown in Figure P8 36 The length of the heating section is 3 m and the heater temperature is 425 C The sidewalls are insulating and it is determined experimentally that the conveyor belt and parts attain a temperature of 120 C The belt part combination has an effective emissivity of 0 8 and the radiant heater surface has 0 7 Calculate the energy supplied to the heater Be sure to consider the radiation that is lost from the ends of the channel Take the surroundings as a blackbody at 25 C

a he value of X 2 9 The decomposition of phosphine PH on tungsten at low pressure is a first order reaction It is because the 2016 II a Rate is proportional to the surface coverage b Rate is inversely proportional to the surface coverage c Rate is independent of the surface coverage d Rate of decomposition is very low

carbon chlorine carbon dioxide copper calcium carbon chlorine copper hydrogen mercury oxygen sodium zinc I Mixtures A Heterogeneous mixtures 1 2 3 Elements Organize information about mixtures in the outline below 4 Examples B Homogeneous mixtures 1 2 3 mercury oxygen 4 Examples water salt sodium sugar Compour sugar carbon dioxide

Change 1 Change 1 is impossible a physical change a chemical change Sample of Substance X Change 2 Change 2 is impossible a physical change a chemical change Change 3 Change 3 is impossible a physical change a chemical change X S

Give an example of a liquid solid suspension

23 Which of the following accurately describes a soap molecule a Can only mix with polar compounds b Only mixes with nonpolar compounds c Soap can mix with both polar and nonpolar compounds d d Cannot mix with either polar or nonpolar compounds Sub 016

5 a C b A solid bre c Individual ions join together to form a so d Spectator ions form a precipitate Which of the following pictures show dissociation BEFORE 8 BEFORE AFTER AFTER b d BEFORE Before AFTER After 00

ons Give a definition or description for the following term Precipitation reaction 10 bo

3 Would you expect the van der Waals interaction between two spherical water droplets in air and two air bubbles in water to be the same if all the spheres are of identical size Explain your answer

Choose which reaction will occur at the fastest rate A 5 0 grams of copper metal in 0 50M HNO3 5 0 grams of copper metal in 0 10M HNO3

Pick the odd one out. Stirring Increase in surface area Increase in pressure Decrease in temperature

Calcium and magnesium ion from a 105 litre sample of hard water was quantitatively precipitated as carbonates and weight of ppt obtained was found to be 568 g. Precipitate lost 264 g of weight on strong heating (A) Degree of hardness of water is 4 ppm (B) Molarity of Ca2+ ions in hard water was 4 x 10-5 M (C) Molarity of Mg2+ ions in hard water was 4 x 10-5 M (D) Sum of molarity of Ca2+ and Mg2+ ions in hard water was 6 x 10-5 M

A substance has a higher temperature when its particles have a higher average kinetic energy. Imagine two different substances that are both pure, meaning they each contain only on type of matter. Each substance has a different temperature. Which two properties determine which substance has the higher temperature?

9) Show the correct link according to description on the right: a) Hypotonic b) Isotonic c) Suspension d) Osmosis e) Dialysis f) Solution Solution has a lower solute concentration as the concentration inside the blood cells (1 point) A homogeneous mixture made up of very small size molecules or ions. Passage of water molecules through a semi-permeable membrane from a solution containing a lower salt concentration to a solution containing a higher salt concentration Small molecules and ions pass through a semi-permeable membrane while large macromolecules are held back Heterogeneous mixture with very large and heavy particles that tend to settle down on the bottom of the container. Solution has the same solute concentration as the concentration inside the blood cells

If you added 35.5 ml of an HCl solution to 35.5 ml of an NaOH solution and the temperature increased from 25.5 °C to 36.5 °C how much heat transferred in this process? The density of the mixture is 1.00 g/ml.

Match the terms about analytical precipitations to their definitions. The adsorption, occlusion, or inclusion of impurities along with the desired analyte in a precipitate. The binding of impurities to the surface of a crystal. The inclusion or occlusion of impurities within a crystal. The process of letting a precipitate stand with the mother liquor to promote slow recrystallization. The process of breaking up of a precipitate upon washing with water in the absence of an electrolyte.

Micelles consist of milk proteins and other molecules suspended in water. a soluble form of vitamin D. aggregates of alcohol molecules. None of these responses is correct. a broken-down form of vitamin D. water-soluble fat molecules.

An oxygen (O₂) molecule is adsorbed on a patch of surface (see sketch at right). This patch is known to contain 289 adsorption sites. The (0₂) molecule has enough energy to move from site to site, so it could be on any one of them. Suppose additional surface becomes exposed, so that 484 adsorption sites are now available for the molecule. Calculate the change in entropy. Round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Identify the improved version of the sentence below. Learning how to knit can be a relaxing and therapeutic activity. It is a good idea for children to learn to knit in school. Some might argue that learning how to knit can be a relaxing and therapeutic activity. However, it is a good Idea for children to learn to knit in school. Learning how to knit, therefore, can be a relaxing and therapeutic activity. For this reason, it is a good idea for children to learn to knit in school. Learning how to knit can be a relaxing and therapeutic activity. It is a good idea for children to learn to knit in school. All of the choices

A sample of water is mixed with a surfactant. What will most likely happen to the viscosity of the water? Explain your answer.

The forces between water molecules are stronger than the forces between ethanol molecules. Which liquid would probably be most difficult for an insect to walk on? Explain your answer.

Describe two uses of surfactants. At least one must be something that was not described in the passage. For each example, explain how the effects of the surfactant make it useful.

A student places a small amount of water in a glass dish and then carefully places a small paperclip on the surface of the water. The paperclip floats. What happens if the student adds a drop or two of dish soap to the water? Explain your answer.

When oil is placed in water, oil is insoluble soluble solvent

is useful to separate mixtures of colored compounds. Spectrometry Electromagnetism Chromatography

What is a watershed? Which watershed do you live in? When it rains at your home, what creek and river does the water travel to?

The protein collagen has an isoelectric point of pl = 6.60. This is the pH at which the number of positive charges on the protein surface equals the number of negative charges on the protein surface. At which of the following solution pH values will collagen be in solution and at which will it tend to aggregate?