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(b) because acetone evaporate very quickly in the atmosphere and also take all the heat from the surrounding that's why we feel cool

See,for a.)it is so because when evaporation occurs,the transfer of heat takes place between the surrounding and the system(from what evaporation is taking place,eg.water).Due to which,on evaporation the water molecules in air which are more warmer in comparison to the surrounding air molecules,absorb heat from the nearby air molecules to attain equilibrium. In the same way,you can think of b.)alsoTry it by yourself.

a) evaporation is an endothermic process and it absorbs heat while evaporating and causes cooling effectb) Whenweput someacetonethen it evaporates andwecould feel cold onpalm. it is becauseAcetoneis called as low boiling liquids. Whenacetone is poured on palmit readily changes into vapours. ... Thus it evaporates andweget acoolingsensation

a catalyst has no effect on the position of equilibrium is because it increases the forwards and backwards rate of reaction in equal measure - so the ratio of the reaction is unchanged. A catalyst does increase the speed at which a system will reach equilibrium though.It doesnt affect the equilibrium concentrations of the reactants or products and thus not the equilibriumconstants . Itjust makes the equilibrium get achieved more faster.

34+32+30+28,,,,,,,+10=286

28+26+24+22+20+18+16+14+12

the answer for 34+32+30+...+10= 286terms = 13difference Between two terms= 2so total is 286

molar mass of HBr = 81 g

=> number of moles of HBr in 8.1 hm = 8.1/81 = 0.1 moles.

HBr ⇔ H⁺ + Br⁻

Hence,

i = 1 + (2-1)x0.9 = 1.9

We know that,

ΔT = i x Kf x 1000 x m/w

= 1.9 x 1.86 x 1000 x 0.1/100

= 3.53

=> Freezing point = 0 - 3.53

= -3.53⁰C

Hence freezing point of the solution will be -3.53⁰C

molarity= no.of moles of solute/volume of the solution in litres.

given that:molarity=0.20 ,no.of moles of solute =0.15.

so, 0.20=0.15/volume of the solution.

volume=0.15/0.20=0.75 lt.

so volume=750ml.

salt of weak acid and weak base

ph=1/2pkw + 1/2pka -1/2pkb

=1/2×14 + 1/2×3.8 -1/2×4.8

=6.5

X’ is in group 13=> x has a valency 3‘Y’ is in group 16=> y has a valency of 2X. Y.3. 2

=> compound is X2Y3

yes we can separate the components

yes we can separate the components

yes we can seperate it

yes in some component we can seperate

Yes we can seperate components from material by certain methods of separation

Noble gases are placed separately in periodic table because : A) They have completely filled outer electronic shell configuration.B) They are inert in nature due to above mentioned regions.C) They all exhibit properties very different from all other elements of the periodic table as they do not make compounds ( there are exceptions tho like compounds of Xenon with oxygen and flourine ).

The answer Of The question is Rn

D is more electro negative as we move from left to right along a period the non metallic characters and electro negativity increases

Electronic Configuration of D (2,8,7)Valency of D is 1 (8-7)

As themandelic acid salt) it is used for the treatment ofurinary tract infection. It decomposes at an acidic pH to form formaldehyde and ammonia, and the formaldehyde is bactericidal; the mandelic acid adds to this effect.

An input device is any hardware device that sends data to a computer, allowing you to interact with and control it.Mouse , keyboard, joystick, scanner, digital camera

input devices are used to feed data or introduction input into a computer some example of input device are Mouse keyboard scaner Z camera joystick microphone

The Xenon atom is larger than the other noble gasses so its outer electrons are farther away from the nucleus and thus a little more loosely held making them subject to interaction with strong electron acceptors. One exception to the above is Radon whose atom is even larger. However Radon is radioactive with a short half life so even though it probably is more reactive, its compounds would not last long.

thnx

20Ca-[Ar]4s^2 ,12Mg-[Ne]3s^2 ,27Co-[Ar]3d^7 4s^2 ,30Zn-[Ar]3d^10 4s^2.

The reason behind the inertness of noble gases is the presence of 8 electrons in their outermost shell.

This means that, their outermost shell is completely filled and they don’t need to take part in chemical reactions to complete octet and achieve stability.

They are already stable and hence, chemically inert.

Chromatographyis used in industrial processes to purify chemicals,

test for trace amounts of substances,

separate chiral compounds

test products for quality control.

Hinsberg Test :It is popular chemical test for the identification of primary, secondary and tertiary amines. In this, an amine is treated withBenzenesulphonyl chloride( Hinsberg reagent) in presence of aqueous alkali (KOH or NaOH). Following observations are found:

Primary amines when treated with Hinsberg reagent gives N-ethylbenzenesulphonyl amide. Due to presence of strong electron withdrawing sulphonyl group, the H attached to nitrogen in sulphonamide is strongly acidic, thus, makes it soluble in alkali.

When secondary amines treated with Hinsberg reagent, N,N-diethylbenzenesulhphonamide is formed. Due to absence of H atom, this compound is not acidic in nature, hence, insoluble in alkali.

With tertiary amines, Hinsberg reagent gives no reaction.

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B)PlatinumIt is not a semiconductor hence it can't be used as a solar cell.

how much NH2?

Galliumis a silvery metal and element number 31 on the Periodic Table, and itmeltsat 85.6 degrees Fahrenheit. That's a temperature low enough forgalliumtomelt in your hand— and unlike the liquid metal mercury,galliumis safe to play with, according to chemists.

Acceleration = 4.2-1.8/1.2

=2.4/1.2

=2m/s^2

Force =m*a

=5.5*2

=11N

Transition elementshave partially filled d orbitals. We also know that when electrons jump from one orbital to another light is emitted due to which the compounds oftransition elementsseem to becoloredcompounds.

thnx sir

the temperature at least a liquid starch start boiling on normal atmospheric pressure is called melting

Themelting-pointsof thetransition metals are highdue to the 3d electrons being available for metallic bonding. The densities of thetransition metals are highfor the same reason as thehigh boiling points.Transition metals areall densemetals with high melting and boiling points.

After theboiling pointthe substance will remain asgas. ... At roomtemperaturethe substanceisat atemperature between melting pointandboiling point. So it Will be aliquid. So the phase of a substanceliquid gasorsoliddepends on theirmelting points,boiling points, roomtemperatureand pressure.

Boiling point:Haloalkanes are generally liquids at room temperature. Haloalkanes generally have a boiling point that is higher than the alkane they are derived from. This is due to the increased molecular weight due to the large halogen atoms and the increased intermolecular forces due to the polar bonds, and the increasing polarizabilty of the halogen.

Physical appearance:Haloalkanes are colourless when pure. However bromo and iodo alkanes develop colour when exposed to light. Many volatile halogen compounds have sweet smell.

Solubility:The haloalkanes are only very slightly soluble in water, but dissolves in organic solvents. This is because for dissolving haloalkanes in water the strong hydrogen bonds present in the latter has to be broken. When dissolved in organic (non polar) solvents, the intermolecular attractions are almost same as that being broken.

The first element of the group is usually small in size and is highly electronegative. Owing to this fact, the first element of these groups undergo hydrogen bonding which makes the boiling point of these compounds exceptionally higher.

I want more meaningful answer ...!

the resason is because of high difference in the electronegativity of hydrogen and fluorine as compared to that of hydrogen and nitrogen, more amount of energy is required to break the hydrogen-fluorine hydrogen bond as compared to the hydrogen-nitrogen bonding .

It is given that equal volumes of HCl and NaOH are present, so let us assume that each has a volume = 1litre.

Volume of NaOH= 1litreMolarity of NaOH = 0.1Moles of NaOH = 0.1x 1 =0.1 [ As the formula says Mole = [Concentration in M x volume in L)]

Volume of HCl present = 1 litreMolarity ofHClpresent = 0.01Moles of HCl = 0.01 x1= 0.01

Equal volume of HCl balance equal volumes of HCl according to the reactionHCl + + NaOH>>NaCl+ H2OThereforeNaOH is present in excess = 0.1-0.01= 0.09molesTotal volume of the solution = 2LConcentration of OH-ions =pOH = -log[OH-] = - log[0.045] = 1.347We know that pH = 14- pOHHence pH of the resultant solution = 14- 1.347 = 12.65

Assuming that the concn. of NaCl is also 0.1 MSuppose volumes mixed are V mL then mmole AgNO3 = NO3 = 0.1 x VNow after mixing total vol. = 2 VSo concn. of NO3 ions( which are spectators in reaction) after mixing = 0.1 x V / 2V =0.05 M

The frequency of the light remains unchanged as it passes through the transparent medium (provide the refracting surface is not changing with time). Under the similar condition, the wavelength and velocity of light will change (so as to keep frequency unchanging). Hence, option (C) is correct.

0.625atm option a

The pH of salt used to make tasty and crispy pakoras is 9.

The baking soda is most commonly used in making tasty pakoras because it's basic in nature. It's chemically known by the name sodium bicarbonate.

The reaction that take place during cooking of food and adding baking soda in it is as follows:-

Uses:-

sodium bicarbonate is used for preparing baking powder and effervescent drink.

sodium bicarbonate is used as antacid.

here ,

sodium hydrogen carbonate is react with hydrochloric acid and form sodium chloride carbon dioxide and water.

due to release of ""carbon dioxide"" it help in rising of pakoda as well as softning of it.

so that due to release of carbon dioxide in pakoda it make rise and make the pakoda tasty and crispy.

colloids are a homogeneous non-crystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second substance. Colloids include gels, sols, and emulsions; the particles do not settle, and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.

An aerosol, sometimes called a liquid aerosol, is a liquid dispersed in agas, such as fog, which is tiny water droplets suspended in air. All gases are inherently miscible (completely soluble in each other), so by definitionthereisnosuch thing as agas-gas colloid

In chemistry, a colloid is a mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance. Sometimes the dispersed substance alone is called the colloid; the term colloidal suspension refers unambiguously to the overall mixture

the dispersed phase (call it gas #1) is already at the molecular level and disperses evenly throughout the dispersing medium (call it gas #2). It is completely homogeneous at the molecular level. It is a solution.

An example of this is the atmosphere. Using only the two major gases, we can consider the atmosphere to be oxygen dissolved into nitrogen.

No,Copper has lesser reactivity than zinc so zinc would replace copper in copper sulphate and will form zinc sulphate

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