Recent questions tagged some-basic-concepts-in-chemistry

An element X (atomic wt. =125) crystallises is simple cubic structure. If diameter of the largest atom which can be placed without disturbing unit cell is $366\;pm$. Find the density of pure element X in $gm/cm^3$ [Given ,$N_A=6 \times 10^{23}]$

asked Jan 18, 2016 by meena.p

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If a solution contains 1 mol of $KMnO_4$ in acidic medium, it will oxidize :

asked Jan 18, 2016 by meena.p

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The molar ratio of $Fe^{2+} to\; Fe^{3+} in\; a\; mixture\; of\; FeSO_4$ and $Fe_2(SO_4)_3$ having equal number of sulphate ion in both ferrous and ferric sulphate is :

asked Jan 18, 2016 by meena.p

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A mixture of $NH_4NO_3$ and $(NH_4)_2HPO_4$ contain $30.4 \%$ mass percent of nitrogen. What is the mass ratio of the two components in the mixture.

asked Jan 18, 2016 by meena.p

1 answer

$0.5\;g$ of fluming $H_2SO_4$(oleum) is diluted with water. This solution is completely neutralised by $26.7\;mL$ of $0.4\;N\;NaOH$. The percentage of free $SO_3$ in the sample is

asked Apr 1, 2014 by meena.p

1 answer

$0.005\;cm$ thick coating of silver is deposited on a plate of $0.5 \;m^2$ area. The number of silver atoms deposited on the plate are (atomic mass of silver $=108$ , and its density $=7.9g cm^{-3}$

asked Apr 1, 2014 by meena.p

1 answer

The density of salt solution is $1.13\;g\;cm^{-3}$ at $298\;k$. The solution contains $17.0 \%$ sodium chloride . What volume of solution will contain $38.42 \;g$ of $NaCl$?

asked Apr 1, 2014 by meena.p

1 answer

Haemoglobin contains $0.33 \%$ of irons by weight. The molecular weight of haemoglobion is approximately $67200$. The number of iron atoms (at wt of $Fe=56$) present in one molecule of haemolgobin is

asked Apr 1, 2014 by meena.p

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A hydrocarbon contains $85.7 \%C$ If $42\;mg$ of the compound contains $3.01 \times 10^{20}$ molecules, the molecular formula of the compound is

asked Apr 1, 2014 by meena.p

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How many g of KCl would have to be dissolved in $60\;g\; H_2O$ to give $20\%$ by weight of solution ?

asked Apr 1, 2014 by meena.p

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$1.12\;mL$ of a gas is produced at STP by the action of $4.12\;mg$ of alcohol ROH with methyl magnesium iodide. The molecular mass of alcohol is

asked Apr 1, 2014 by meena.p

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Substance is found to contain $7 \%$ nitrogen, The minimum molecular weight of it is

asked Mar 31, 2014 by meena.p

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Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen. The weight of lead from one oxide was half the weight of lead obtained from the other oxide. The data illustrates

asked Mar 31, 2014 by meena.p

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The mass of a piece of paper is $0.02\;g$ and the mass of a solid substance along with the same piece of paper is $20.036\;g$. If the volume of the solid is $2.16\;cm^3$ its density to the proper number of significant digits will be

asked Mar 31, 2014 by meena.p

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Two Containers P and Q of equal volume (1 litre each) contain 6g of $O_2$ and $SO_2$ respectively at $300\;k$ and 1 atmosphere then,

asked Mar 31, 2014 by meena.p

1 answer

When a sample of human blood is diluted $200$ times its initial volume and microscopically examined in a layer $0.10\;mm$ thick , an average of $30\;RBC$ are found in $100 \times 100 $ micrometer square. The number of RBC in $1 \;mm^3$ of undiluted blood is

asked Mar 31, 2014 by meena.p

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What quantity of limestone $(CaCO_3)$ on heating will give $56\;kg$ of $CaO$?

asked Mar 31, 2014 by meena.p

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The Loschmidt number is the number of

asked Mar 31, 2014 by meena.p

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

asked Mar 31, 2014 by meena.p

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Among $FeSO_4.7H_2O(A),CuSO_4.5H_2O (B), ZnSO_4.7H_20(c),MnSO_4.4H_2O $(D), isomorphous salts are

asked Mar 28, 2014 by meena.p

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The atomic weights of two elements A and B are 40 and 80 respectively . If xg of A contains y atoms, how many atoms are present in $2x\;gram$ of B?

asked Mar 28, 2014 by meena.p

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Which of the following is isomorphous with magnesium sulphate $(Mg SO_4. 7H_2O)$?

asked Mar 28, 2014 by meena.p

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The charge on 1 gram ion of $Al^{3+}$ is :

asked Mar 28, 2014 by meena.p

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The unit $J\; Pa^{-1}$ is equivalent to

asked Mar 28, 2014 by meena.p

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A balanced chemical equation is in accordance with

asked Mar 28, 2014 by meena.p

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Which of the following has three significant figures ?

asked Mar 28, 2014 by meena.p

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Find the equivalent weight of $H_3PO_4$ in the reaction. $Ca(OH)_2 +H_3 PO_4 \to CaHPO_4+2H_2O$

asked Mar 28, 2014 by meena.p

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How many milliliters of $0.5\;M\;H_2SO_4$ are needed to dissolve $0.5\;g$ of copper (II) carbonate ?

asked Mar 28, 2014 by meena.p

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A plant virus is found to consists of uniform cylindrical particles of $150 A^{\circ}$ in diameter and $5000\;A^{\circ}$ long. The specific volume of the virus is $0.75\;cm^3/g$ If the virus is considered to be a single particle , find its molar mass.

asked Mar 28, 2014 by meena.p

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Calculate the molarity of water if its density is $1000 kg/m^3$

asked Mar 28, 2014 by meena.p

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Calculate the molality of 1 litre solution of $93 \ % H_2SO_4 $ (weight / volume). the density of the solution is $1.84\;g/ml$.

asked Mar 28, 2014 by meena.p

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$2.68 \times 10^{-3} $ moles of a solution containing an ion $A^{n+}$ acqired. $1.81 \times 10^{-3}$ moles of $MnO_4^{-}$ for the oxidation of $An^{+} +0 AO_3^{-}$ in acid medium. What is the value of n

asked Mar 27, 2014 by meena.p

1 answer

Statement 1: In the titration of $Na_2CO_3$ with $Hcl$ using methyl orange indicator, the volume required at the equivalence point is twice that of the acid required using phenolphthalein indicator Statement 2: Two moles of $HCl$ are required for the complete neutralization of one mole of $Na_2CO_3$ .

asked Mar 27, 2014 by meena.p

1 answer