Recent questions tagged unit1

The percentage of oxygen in NaOH is

asked Mar 25, 2014 by sreemathi.v

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A gas is found to have formula $[CO]_x$.If its vapour density is 70 then the value of x is

asked Mar 25, 2014 by sreemathi.v

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In alkaline medium,$KMnO_4$ reacts as follows:$2KMnO_4+2KOH\rightarrow 2K_2MnO_4+H_2O+O$.Therefore,the equivalent weight of $KMnO_4$,will be

asked Mar 25, 2014 by sreemathi.v

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The relative abundance of two isotopes of atomic weight 85 and 87 is 75% and 25% respectively.The average atomic weight of element is

asked Mar 25, 2014 by sreemathi.v

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'M' g of an element gave 'N' g of oxide.Equivalent weight of the element is

asked Mar 25, 2014 by sreemathi.v

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A container of volume V contains 0.28g of $N_2$ gas.If the same volume of an unknown gas under similar conditions of temperature and pressure weighs 0.44g,the molecular mass of the gas is

asked Mar 25, 2014 by sreemathi.v

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112.0ml of $NO_2$ at STP was liquefied,the density of the liquid being $1.15gmL^{-1}$.Calculate the volume and the number of molecules in the liquid $NO_2$.

asked Mar 25, 2014 by sreemathi.v

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X and Y are two elements which form $X_2Y_3$ and $X_3Y_4$.If 0.20mol of $X_2Y_3$ weighs 32.0g and 0.4mol of $X_3Y_4$ weighs 92.8g.The atomic weights of X and Y are respectively

asked Mar 25, 2014 by sreemathi.v

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The number of gram atoms of oxygen present in 0.3 gram mole of $H_2C_2O_4.2H_2O$(oxalic acid) is

asked Mar 25, 2014 by sreemathi.v

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If $N_A$ is the Avogadro's number then number of valence electrons in 4.2g of nitride ion($N^{3-})$ is

asked Mar 25, 2014 by sreemathi.v

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At STP ( standard temperature and pressure ) 40L of $CO_2$ contains

asked Mar 25, 2014 by sreemathi.v

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If the Avogadro's number is $1\times 10^{23}$ mol$^{-1}$ then the mass of one atom of oxygen would be

asked Mar 25, 2014 by sreemathi.v

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Chemical reactions involve interaction of atoms and molecules.A large number of atoms/molecules are present in a few grams of any chemical compound varying with their atomic/molecular masses.To handle such large numbers conveniently,the mole concept was introduced.This concept has implications in diverse areas such as analytical chemistry,biochemistry,electrochemistry and radiochemistry.The following example illustrates a typical case involving chemical/electrochemical reaction.A H.O molar aqueous solution of NaCl is prepared and 500ml of this solution is electrolysed.This leads to the evolution of chlorine gas at one of the electrodes(atomic mass:Na=23,Hg=200;1 faraday=96500 coulombs).The total charge (coulombs) required for complete electrolysis is

asked Mar 25, 2014 by sreemathi.v

1 answer

Chemical reactions involve interaction of atoms and molecules.A large number of atoms/molecules are present in a few grams of any chemical compound varying with their atomic/molecular masses.To handle such large numbers conveniently,the mole concept was introduced.This concept has implications in diverse areas such as analytical chemistry,biochemistry,electrochemistry and radiochemistry.The following example illustrates a typical case involving chemical/electrochemical reaction.A H.O molar aqueous solution of NaCl is prepared and 500ml of this solution is electrolysed.This leads to the evolution of chlorine gas at one of the electrodes(atomic mass:Na=23,Hg=200;1 faraday=96500 coulombs).If the cathode is a Hg electrode,the maximum weight (g) of amalgam formed from this solution is

asked Mar 25, 2014 by sreemathi.v

1 answer

Chemical reactions involve interaction of atoms and molecules.A large number of atoms/molecules are present in a few grams of any chemical compound varying with their atomic/molecular masses.To handle such large numbers conveniently,the mole concept was introduced.This concept has implications in diverse areas such as analytical chemistry,biochemistry,electrochemistry and radiochemistry.The following example illustrates a typical case involving chemical/electrochemical reaction.A H.O molar aqueous solution of NaCl is prepared and 500ml of this solution is electrolysed.This leads to the evolution of chlorine gas at one of the electrodes(atomic mass:Na=23,Hg=200;1 faraday=96500 coulombs).The total number of moles of chlorine gas evolved is:

asked Mar 25, 2014 by sreemathi.v

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What volume of $CO_2$ will be liberated at NTP if 1.2g of carbon is burnt in excess of oxygen?

asked Mar 25, 2014 by sreemathi.v

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The specific heat of a metal is 0.11 and its equivalent weight is 18.61.Its exact atomic weight is

asked Mar 25, 2014 by sreemathi.v

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$6.0\times 10^{20}$ molecules of urea are present in 100ml of its solution .The concentration of urea solution is

asked Mar 25, 2014 by sreemathi.v

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A compound possesses 8% sulphur by mass.The least molecular mass is

asked Mar 25, 2014 by sreemathi.v

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The number of atoms in 4.25g of $NH_3$ is approximately

asked Mar 25, 2014 by sreemathi.v

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5.85g of NaCl is dissolved in 1L of pure water.The number of ions in 1ml of this solution is

asked Mar 25, 2014 by sreemathi.v

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20g of sample of $Ba(OH)_2$ is dissolved in 50c.c of 0.1N HCl solution.The excess of HCl has titrated with 0.1NaOH.The volume of NaOH used was 20c.c.Calculate percentage of $Ba(OH)_2$ in the sample

asked Mar 24, 2014 by sreemathi.v

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Number of atoms in 558.5 g Fe (at.wt of Fe=$55.85gmol^{-1})$ is

asked Mar 21, 2014 by sreemathi.v

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From 392mg of $H_2SO_4,1.204\times 10^{21}$ molecules are removed.How many moles of $H_2SO_4$ are left?

asked Mar 21, 2014 by sreemathi.v

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There are as many notes as number of oxygen atoms in 24.8g $Na_2S_2O_3.5H_2O$ (molecular weight =$248gmol^{-1})$.A note-counting machine counts 48 million notes per day.Days taken to count these notes are

asked Mar 21, 2014 by sreemathi.v

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The atomic weight of Cu is 63.546.There are only two naturally occuring isotopes of copper,$^{63}Cu$ and $^{65}Cu$.The relative abundance of the $^{63}Cu$ isotope must be

asked Mar 21, 2014 by sreemathi.v

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$2H_2+O_2\rightarrow 2H_2O$.2g $H_2$ and 1g $O_2$ react to form $H_2O$

asked Mar 21, 2014 by sreemathi.v

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The equivalent mass of chlorine is 35.5 and the molar mass of copper is 63.5.The equivalent mass of copper chloride is 99.0.Hence formula of copper chloride is

asked Mar 21, 2014 by sreemathi.v

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The equivalent weight of an element is 4.Its chloride has a vapour density 59.25.Then the valency of the element is

asked Mar 21, 2014 by sreemathi.v

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The reaction , $3Cl_O(aq) \longrightarrow ClO_{3(ag)}^{-}+2 Cl^{-}_ {(aq)}$ is an example of

asked Mar 21, 2014 by meena.p

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The number of neutrons in dipositive zinc ion with mass number 70 is

asked Mar 21, 2014 by meena.p

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If $0.50$ mol of $Bacl_2$ is mixed with $0.20$ mol of $Na_3PO_4$ , the maximum number of moles of $Ba_3(PO_4)_2$ that can be formed is

asked Mar 21, 2014 by meena.p

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A gaseous mixture contains oxygen and nitrogen in the ratio of $1:4$ by weight . Therefore , the ratio of their number of molecules is

asked Mar 21, 2014 by meena.p

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In the standardization of $Nas_2S_2O_3$ using $K_2Cr_2O_7$ by iodometry , the equivalent weight of $K_2Cr_2O_7$ is

asked Mar 21, 2014 by meena.p

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Consider a titration of potassium dichromate solution with acidified Mohr's salt solution using diphenylamine as indicator. The number of moles of Mohr's salt required per mole of dichromate is

asked Mar 21, 2014 by meena.p

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How many moles of electron weight one kilogram ?

asked Mar 21, 2014 by meena.p

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The number of moles of $KMnO_4$ that will be needed to react completely with one mole of ferrous oxalate in acidic solution is

asked Mar 21, 2014 by meena.p

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$2.76\;g$ of silver carbonate on being strongly heated yields a residue weighing.

asked Mar 21, 2014 by meena.p

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Which has the maximum number of atoms?

asked Mar 21, 2014 by meena.p

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Given that the abundance of isotopes $^{54}Fe, ^{56}Fe$ and $^{56}Fe$ are $5 \%, 90 \%$ and $5 \%$ respectively, the atomic mass of $Fe$ is

asked Mar 21, 2014 by meena.p

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The largest number of molecules is in

asked Mar 21, 2014 by meena.p

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An aqueous solution of $6.3\;g$ oxalic acid dihydrate is made up to $250\;ml$ . The volume of $0.1\;N\; NaOH$ required to completely neutralize 10 ml of this solution is

asked Mar 21, 2014 by meena.p

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The normality of $0.3\;M$ phosphorous acid $(H_3P0_3) $ is

asked Mar 21, 2014 by meena.p

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When the same amount of zinc is treated separately with excess of sulphuric acid and excess of sodium hydroxide evolved is

asked Mar 21, 2014 by meena.p

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The total number of electrons in one molecule of carbon dioxide is

asked Mar 21, 2014 by meena.p

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The equivalent weight of $ MnSO_4$ is half its molecular weight when it is converted to

asked Mar 21, 2014 by meena.p

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A molal solution is one that contains one mole of a solute in

asked Mar 20, 2014 by meena.p

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A match box exhibits :

asked Feb 27, 2014 by sharmaaparna1

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At room temperature , Sodium crystallizes in a b.c.c lattice with edge length $a = 4.24A^{\large\circ}$ . Find the theoretical density of sodium.

asked Feb 25, 2014 by sharmaaparna1

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The density of KBr is 2.73g/cm. The length of the unit cell is 654pm. Find the number of atoms per unit cell in the cubic structure.

asked Feb 25, 2014 by sharmaaparna1

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