Recent questions tagged physical-chemistry

A drop (0.05ml) of 12M HCl is spread over a thin sheet of aluminum foil (thickness 0.10mm and density of Al=2.70g/ml).Assuming whole of the HCl is used to dissolve Al,what will be the maximum area of hole produced in foil?

asked Jan 7, 2014 by sreemathi.v

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Calculate molality of 1 litre solution of $93\%$ $H_2SO_4$ by volume.The density of solution is $1.84\; g$ $mL^{-1}$

asked Jan 7, 2014 by sreemathi.v

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A 6.90M solution of KOH in water has 30% by weight of KOH. Calculate the density of the solution.

asked Jan 7, 2014 by sreemathi.v

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A piece of Al weighing $2.7g$ is titrated with $75\;ml$ of $H_2SO_4$ (specific gravity = $1.18gmL^{-1}$ and $24.7%$ $H_2SO_4$ by weight). After the metal is completely dissolved, the solution is diluted to $400\;ml$. Calculate molarity of free $H_2SO_4$ in solution.

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

4.08g of a mixture of BaO and unknown carbonate $(MCO_3)$ was heated strongly.The residue of 3.64g was dissolved in 100ml of 1N HCl.The excess acid required 16ml of 2.5N NaOH solution for complete neutralization.Identify metal

asked Jan 7, 2014 by sreemathi.v

1 answer

A small amount of $CaCO_3$ completely neutralized 525ml of N/10 HCl and no acid is left at the end.After converting all calcium chloride to $CaSO_4$,how much plaster of paris can be obtained?

asked Jan 7, 2014 by sreemathi.v

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25ml of a solution of $Na_2CO_3$ having a specific gravity of $1.25ml^{-1}$ required 32.9ml of a solution of HCl containing 109.5g of the acid per litre for complete neutralization .Calculate the volume of 0.84N $H_2SO_4$ that will be completely neutralized by 125g of $Na_2CO_3$ solution.

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

1.20g sample of $Na_2CO_3$ and $K_2CO_3$ was dissolved in water to form 100ml of a solution.20ml of this solution required 40ml of 0.1N HCl for complete neutralization.Calculate the weight of $Na_2CO_3$ in mixture. If another 20 ml of this solution is treated with excess of $BaCl_2$,what will be the weight of precipitate?

asked Jan 6, 2014 by sreemathi.v

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A mixture of ethane $(C_2H_6)$ and ethene $(C_2H_4)$ occupies 40 litre at 1.00atm and at 400k.The mixture reacts completely with 130g of $O_2$ to produce $CO_2$ and $H_2O$.Assuming ideal gas behavior ,Calculate the mole fractions of $C_2H_4$ and $C_2H_6$ in the mixture.

asked Jan 6, 2014 by sreemathi.v

1 answer

Consider following reaction: $Mg(s)+2HCl(aq)\rightarrow H_2(g)+MgCl_2(aq)$.The rate of this reaction increases when more magnesium is added.This change is due to

asked Dec 19, 2013 by sreemathi.v

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Consider the reaction $2H_2O_2(aq)\rightarrow 2H_2O(l)+O_2(g)$ wen 1g of KI is added to $H_2O_2$,bubbles of $O_2$ are produced at an increased rate.When reaction is complete,mass of KI is 1g.The KI is a

asked Dec 19, 2013 by sreemathi.v

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For reaction $X+Y\rightarrow Z$ the reaction rate is found to depend only upon concentration of X. A plot of $\large\frac{1}{[X]}$ vs time gives a straight line. What is rate law for this reaction?

asked Dec 19, 2013 by sreemathi.v

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Which of following is incorrect?

asked Dec 19, 2013 by sreemathi.v

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Which of following statements is incorrect for a first order reaction, where $T_x$ is the time taken for the reactant to drop by that % number.

asked Dec 19, 2013 by sreemathi.v

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What is the relation between half life ($t_{1/2}$) and temperature for an $n^{th}$ order reaction ;$n > 2$

asked Dec 19, 2013 by sreemathi.v

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The rate law for decomposition of $N_2O_5: N_2O_5\rightarrow 2NO_2+\large\frac{1}{2}$$O_2$ is consistent with observed rate law.If $k'=5\times 10^{-4}s^{-1}$ the time required for $[N_2O_5]$ be reduced to 10% of its original value.

asked Dec 19, 2013 by sreemathi.v

1 answer

For thermal decomposition of ozone to oxygen:Step (i):$O_3\;\;\;\overset{\overset{k_1}{\rightleftharpoons}}{k_{-1}}\;\;\; O_2+O$.Step (ii):$O_3+O\;\;\;\underrightarrow{k_2}\;\;\;2O_2$ then rate will be $\{k_{-1}[O_2] > > k_2[O_3]\}$

asked Dec 19, 2013 by sreemathi.v

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The ratio of $\large\frac{t_{1/2}}{t_{3/4}}$ for $n^{th}$ order is

asked Dec 19, 2013 by sreemathi.v

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The inactivation of a viral preparation is found to be first order reaction.If in beginning $1.5\%$ of virus is inactivated then calculate time required for 50V inactivation.

asked Dec 19, 2013 by sreemathi.v

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For following data for hydrolysis of benzene diazonium chloride $C_6H_5-N=N-Cl+H_2O\rightarrow C_6H_5OH+HCl+N_2(g)$, What is the first order calculate rate constant?

asked Dec 19, 2013 by sreemathi.v

1 answer

The gas -phase thermal decomposition of one mole of $(CH_3)_3CO_2C(CH_3)_3$ in a constant volume apparatus yields two moles of acetone and one mole of ethane.If the reaction obeys ${1^{st}}$ order then which of the following is true?

asked Dec 19, 2013 by sreemathi.v

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From following data of decomposition of ammonium nitrate in aqueous solution, Determine the order of reaction:

asked Dec 19, 2013 by sreemathi.v

1 answer