Recent questions tagged percentage-composition

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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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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The composition of a sample of Wustite is $Fe_{0..93}O_{1.00}$.What percentage of the iron is present in the form of $Fe(III)$?

asked Mar 26, 2014 by sreemathi.v

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Zinc sulphate contains 22.65% of zinc and 43.9% of water of crystallization. If the law of constant proportions is true, then the weight of zinc required to produce 20g of the crystals will be

asked Mar 26, 2014 by sreemathi.v

1 answer

The percentage of nitrogen in urea is about?

asked Mar 26, 2014 by sreemathi.v

1 answer

The percentage of oxygen in NaOH is

asked Mar 25, 2014 by sreemathi.v

1 answer

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

1 answer

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

1 answer

A mixture of FeO and $Fe_3O_4$ when heated in air to a constant weight,gains 5% of its weight,Find the composition of the initial mixture.

asked Jan 8, 2014 by sreemathi.v

1 answer

A solution contains 4g of $Na_2CO_3$ and NaCl 250ml.25ml of this solution required 50ml of N/10 HCl for complete neutralization.Calculate % composition of mixture.

asked Jan 7, 2014 by sreemathi.v

1 answer

A sample containing 0.4775g of $(NH_4)_2C_2O_4$ and inert materials was dissolved in water and made strongly alkaline with KOH ,which converted $NH_4^+$ to $NH_3$.The liberated ammonia was distilled into exactly 50.0ml of 0.05035M $H_2SO_4$.The excess $H_2SO_4$ was back titrated with 11.3ml of 0.1214M $NaOH$.Calculate percent of N,percent of $(NH_4)_2C_2O_4$.(Mol.wt of $(NH_4)_2C_2O_4=124.10$ and at .wt.of N=14.0078)

asked Jan 7, 2014 by sreemathi.v

1 answer

$2.0g$ of a mixture of carbonate ,bicarbonate and chloride of sodium on heating produced 56ml of $CO_2$ at NTP 1.6g of the same mixture required 25ml of 1N HCl solution for neutralization.Calculate percentage of each component present in mixture

asked Jan 7, 2014 by sreemathi.v

1 answer

$1\;g$ of impure $Na_2CO_3$ is dissolved in water and the solution is made upto $250\;ml$. To $50\;ml$ of this made up solution, $50\;ml$ of $0.1\;N\; HCl$ is added and the mixture after shaking well, required $10\;ml$ of $0.16\;N\; NaOH$ solution for complete neutralization. Calculate $\%$ purity of the sample of $Na_2CO_3$

asked Jan 7, 2014 by sreemathi.v

1 answer

$1.387g$ of a sample containing KCl and $NH_4Cl$ is heated until constant weight.The residue is dissolved in 20ml of N/10 $AgNO_3$ solution.Calculate % of chlorine in mixture.

asked Jan 7, 2014 by sreemathi.v

1 answer

n-Butane is produced by the monobromination of ethane followed by word reaction .Calculate the volume of ethane at NTP to produce 55g n-butane if the bromination takes place with 90% yield and worth reaction with 85% yield.

asked Nov 6, 2013 by sreemathi.v

1 answer

A sample of Mg was burnt in air to give a mixture of MgO and $Mg_3N_2$.The ash was dissolved in 60meq. of HCl and the resulting solution was back titrated with NaOH.12meq of NaOH were required to reach the end point.An excess of NaOH was added and the solution distilled.The ammonia released was then trapped in 10Meq of second acid solution .Back titration of this solution required 6Meq of the base.Calculate the percentage of Mg burnt to the nitride.

asked Nov 6, 2013 by sreemathi.v

1 answer

Consider the decomposition reaction of nitroglycerine $4C_3H_5N_3O_9\rightarrow 6N_2+12CO_2+10H_2O+O_2$. If $200g$ nitroglycerine gives 6.55g $O_2$, then percent yield of the reaction is

asked Oct 29, 2013 by sreemathi.v

1 answer

One litre of $CO_2$ is passed over hot cake.The volume becomes 1.4litre.The percent composition of products is

asked Oct 28, 2013 by sreemathi.v

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A partially dried clay mineral contains 8% water.The original sample contained 12% water and 45% silica.The % of silica in the partially dried sample in nearly :

asked Oct 25, 2013 by sreemathi.v

1 answer

The percentage of sodium in a break-fast cereal,labelled as 110mg of sodium per 100g of cereal is

asked Oct 25, 2013 by sreemathi.v

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$Al_2(SO_4)_3.XH_2O$ has 8.1% aluminum by mass.The value of $X$ is

asked Oct 25, 2013 by sreemathi.v

1 answer

The hydrated salt,$Na_2SO_4.nH_2O$ undergoes 55.9% loss in weight on heating and becomes anhydrous.The value of n will be

asked Oct 25, 2013 by sreemathi.v

1 answer