Recent questions tagged medium

Calculate the mole fraction of ethylene glycol $(C_2H_6O_2)$ in a solution containing 20% of $C_2H_6O_2$ by mass.

asked Aug 8, 2014 by sreemathi.v

1 answer

What is the mole fraction of a solute,in 2.5m aqueous solution?

asked Aug 8, 2014 by sreemathi.v

1 answer

A 0.1539 molal aqueous solution of cane sugar (mol mass =$342gmol^{-1}$) has a freezing point of 271K while the freezing point of pure water is $273.15K$.What will be the freezing point of an aqueous solution containing 5g of glucose (mol mass =$180gmol^{-1}$) per 100g of solution.

asked Aug 8, 2014 by sreemathi.v

1 answer

The freezing point of a solution containing 0.2g of acetic acid is 20.0g of benzene is lowered by $0.45^{\large\circ}$C.Calculate Van't Hoff factor .[For benzene,$K_f=5.12Kkg mol^{-1}]$.What conclusion can you draw from the value of Van't Hoff factor obtained.

asked Aug 8, 2014 by sreemathi.v

1 answer

What concentration of nitrogen should be present in a glass of water at room temperature.Assume a temperature of $25^{\large\circ}C$,a total pressure of atmosphere and mole fraction of nitrogen in air of 0.78.[$K_H$ for nitrogen =$8.42\times 10^{-7}$M/mm Hg]

asked Aug 8, 2014 by sreemathi.v

1 answer

Calculate the molarity and molality of a 15% solutions (by weight) of sulphuric acid density $1.020g cm^{-3}$.(Atomic masses H=10=16S=32 amu)

asked Aug 8, 2014 by sreemathi.v

1 answer

Calculate the radius of molybdenum atom if the element crystallizes as body- centred cubic crystals. Given: Density of $Mo=10.3\;g\;cm^{-3}$ and molar mass of $Mo= 95.94 \;g\;mol^{-1}$

asked Aug 8, 2014 by meena.p

1 answer

A 6.90 M solution of KOH in water contains 30% by mass of KOH.Calculate the density of the KOH solution ?[Molar mass of KOH=$56g mol^{-1}$]

asked Aug 8, 2014 by sreemathi.v

1 answer

Calculate the freezing point of a solution containing 0.520g glucose $(C_6H_{12}O_6)$ dissolved in 80.20g of water.For water $K_f=1.86Kkg mol^{-1}$

asked Aug 8, 2014 by sreemathi.v

1 answer

The freezing point of 0.02 mole fraction solution of acetic acid in benzene is 277.4K.Assuming molality equal to molarity,calculate $K_c$ for the equilibrium reaction $2CH_3COOH\;\;\leftrightharpoons\;\;(CH_3COOH)_2$.Given : $T_f$(benzene) =$278.4$ and $K_f$(benzene)=5.0K kg $mol^{-1}$.

asked Aug 8, 2014 by sreemathi.v

1 answer

100mg of a protein is dissolved in just enough water to make 10.0mL of solution.If this solution has an osmotic pressure of 13.3mm Hg at $25^{\large\circ}C$,what is the molar mass of the protein?(R=0.0821Latm $mol^{-1}K^{-1}$,760mm Hg =1atm)

asked Aug 8, 2014 by sreemathi.v

1 answer

A $ 0.004\;M$ solution of $K_2SO_4$ is isotonic with a $0.010\;M$ Solution of glucose at the same temperature . Tge apparent per cent degree of dissociation of $K_2SO_4$ is

asked Aug 7, 2014 by meena.p

1 answer

Which of the following pairs of solutions are expected to be isotonic?

asked Aug 7, 2014 by meena.p

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In the phenomenon of osmosis through the semipermeable membrane

asked Aug 7, 2014 by meena.p

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The Freezing point of ether was lowered by $0.60^{\large\circ}$C on dissolving 2.0gm of phenol in 100g of ether.Calculate the molar mass of phenol and comment on the result.Given $K_f$(ether)=$5.12Kkg mol^{-1}$

asked Aug 7, 2014 by sreemathi.v

1 answer

The molal elevation constant for water is $0.510Kmol^{-1}kg$.Calculate the boiling point of solution made by dissolving 6g urea in 200g water.

asked Aug 7, 2014 by sreemathi.v

1 answer

The freezing point of a solution containing 0.2g of acetic acid in 20.0g benzene is lowered by $0.45^{\large\circ}$C.Calculate the degree of association of acetic acid in benzene.Assume acetic acid dimerizes in benzene $K_f$ for benzene is $5.12Kmol^{-1}kg$.

asked Aug 7, 2014 by sreemathi.v

1 answer

A solution containing $0.5\;g$ of a solute (molar mass 130 g\;mol^{-1})$ in $50 \;g\;CCl_4$ yields a boiling point elevation of boiling point . The molar mass of solute is about

asked Aug 7, 2014 by meena.p

1 answer

Calculate the freezing point of an aqueous solution of a non-electrolyte having an osmotic pressure 2.0atm at 300K.$K_f=1.86Kmol^{-1}kg$ and $S=0.0821$litre atm $K^{-1}mol^{-1}$

asked Aug 7, 2014 by sreemathi.v

1 answer

Calculate the weight of a non volatile solute having molecular weight 40,which should be dissolved in 114gm octane to reduce its vapour pressure to 80%.

asked Aug 7, 2014 by sreemathi.v

1 answer

The degree of dissociation of $Ca(NO_3)_2$ in a dilute aqueous solution containing 7g of salt per 100g of water at $100^{\large\circ}$C is 70%.Calculate the vapour pressure of solution.

asked Aug 7, 2014 by sreemathi.v

1 answer

Find the molality of a solution containing a non-volatile solute if the vapour pressure is 2% below the vapour pressure of pure water.

asked Aug 7, 2014 by sreemathi.v

1 answer

The solvent $CS_2$ has enthalpy of vapourization of $352\;J\;g^{-1}$ and boiling point equal to $320\;K$. The value of $K_b$ for this solvent is about.

asked Aug 7, 2014 by meena.p

1 answer

An antifreeze solution is prepared from 222.6 of ethylene glycol and 200g of water.If the density of the solution is $1.072gmL^{-1}$,then what shall be the molarity of solution.

asked Aug 7, 2014 by sreemathi.v

1 answer

A solvent of molar mass $84.2 \;g\;mol^{-1}$ and boiling point $81.4^{\circ}C$ has boiling point elevation constant equal to $ 2.79 \;K\;kg\;mol^{-1}$. Its molar enthalpy of vapourization will be about

asked Aug 7, 2014 by meena.p

1 answer

An antifreeze solution is prepared from 222.6 of ethylene glycol and 200g of water.Calculate the molality of the solution.

asked Aug 7, 2014 by sreemathi.v

1 answer

A sucrose solution in 50 g water boils at $100.15^{\circ}C$ , If this solution is heated till its temperature is $100.375^{\circ}C$, how much of water is evaporated ? Given :$ K_b(water)=0.52\;K\;kg\;mol^{-1}$

asked Aug 7, 2014 by meena.p

1 answer

An involatile solute A dimerizes in a solvent as $2A \rightleftharpoons A_2$ . If m is the molarity of solute in the solution , then the equilibrium constant of the reaction is given as

asked Aug 6, 2014 by meena.p

1 answer

The elevation in boiling point when $20.16\;g$ of freshly prepared $CuCl_2$ (relative molar mass : $134.4$) is dissolved in $1\;kg$ of water $(K_b=0.52\;kg\;K \;mol^{-1})$ is

asked Aug 6, 2014 by meena.p

1 answer

To $500cm^3$ of water $3.0\times 10^{-3}$kg of acetic acid is added .If 2.3% of acetic acid is dissociated.What will be the depression of freezing point?$K_f$ and density of water are $1.86$K kg/mol and $0.997g/cm^3$ respectively.

asked Aug 6, 2014 by sreemathi.v

1 answer

When mercuric iodide is added to an aqueous solution of potassium iodide, the

asked Aug 6, 2014 by meena.p

1 answer

The freezing point of a solution containing 0.2g of acetic acid in 20.0g benzene is lowered by $0.45^{\large\circ}$C.Calculate the degree of association of acetic acid in benzene.Assume acetic acid dimerises in benzene.$K_f$ for benzene =$5.12Kmol^{-1}Kg$

asked Aug 6, 2014 by sreemathi.v

1 answer

The elevation of boiling point of water produced by dissolving $1.17 g$ sodium chloride in $100 g$ water $K_b=0.512\;K\;kg\;mol^{-1})$ is

asked Aug 6, 2014 by meena.p

1 answer

If boiling point of an aqueous solution is 100.1$^{\large\circ}C$,what is its freezing point.Given,latent heat of fusion and vaporization of water as $80cal g^{-1}$ and $540cal g^{-1}$ respectively.

asked Aug 6, 2014 by sreemathi.v

1 answer

The boiling point of water at $735$Torr is $99.07^{\circ}C$ . The mass of $NaCl$ added in $100\;g$ water $(K_b=0.51\;K\;kg\;mol^{-1})$ to make its boiling point $100^{\circ}C$ is

asked Aug 6, 2014 by meena.p

1 answer

A very small amount of a non-volatile solute (that does not dissociate) is dissolved in $56.8cm^3$ of benzene (density $=0.889gcm^{-3}$).At room temperature vapour pressure of this solution is 98.88mm Hg while that of benzene is 100 mm Hg.Find the molality of this solution.If the freezing temperature of this solution is 0.73 degree lower than that of benzene .What is the value of $K_f$ for benzene?

asked Aug 6, 2014 by sreemathi.v

1 answer

Which of the following solvents has the largest value of $K_f$?

asked Aug 6, 2014 by meena.p

1 answer

The molar mass and the freezing point of camphor are $152.2\;g\;mol^{-1} $ and $178.4^{\circ} C $ respectively . The cryoscopic constant of camphor is $ 37.7\;K\;kg\;mol^{-1}$, the molar enthalpy of fusion of camphor is about

asked Aug 6, 2014 by meena.p

1 answer

Find the molality of a solution containing a non-volatile solute if the vapour pressure is 2% below the vapour pressure of pure water.

asked Aug 6, 2014 by sreemathi.v

1 answer

The solubility of oxygen in water is $2.43\times 10^{-3}$ mole/litre at $25^{\large\circ}$C and 1.0atm pressure.Calculate the concentration of oxygen at $25^{\large\circ}$C and 0.2atm pressure.

asked Aug 6, 2014 by sreemathi.v

1 answer

A sample of sulphuric acid is 98% $H_2SO_4$ by weight (density =$1.10gmL^{-1})$.Calculate normality

asked Aug 6, 2014 by sreemathi.v

1 answer

If the freezing point depression constant of a solvent is $20.0\;K\;kg\;mol^{-1}$. If its $\Delta_{fus} H^0_m=2.74\;kJ\;mol^{-1}$ and its molar mass is $84.2\;g\;mol^{-1}$ the normal freezing point of the solvent would be about

asked Aug 6, 2014 by meena.p

1 answer

A sample of sulphuric acid is 98% $H_2SO_4$ by weight (density =$1.10gmL^{-1})$.Calculate Molarity

asked Aug 6, 2014 by sreemathi.v

1 answer

For water , $ \Delta _{fus} H^3_m=2.74 \;kJ\;mol^{-1}$ and its molar mass is $ 84.2\;g \;mol^{-1} $ the normal freezing point depression constant at 1 atm pressure would be about

asked Aug 6, 2014 by meena.p

1 answer

1.23g of sodium hydroxide (molar mass =40) are dissolved in water and the solution is made to $100cm^3$.Calculate the molarity of solution.

asked Aug 6, 2014 by sreemathi.v

1 answer

When $20\;g$ of naphthoic acid $(C_{11}H_gO_2)$ is dissolved in $50 \;g$ of benzene $(K_t =1.72\;K\;kg\;mol^{-1}).$, a freezing point depression of $2 K$ is observe. The van't Hoff factor (i) is

asked Aug 6, 2014 by meena.p

1 answer

Determine the osmotic pressure of a solution prepared by dissolving 25 mg of $K_2SO_4$ in 2 litre of water at 25$^{\large\circ}$ C, assuming that it is completely dissociated.

asked Aug 6, 2014 by sreemathi.v

1 answer

The unit of freezing point depression constant is

asked Aug 6, 2014 by meena.p

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The freezing point of a $0.05$ molal solution of a nonelectrolyte in water is

asked Aug 6, 2014 by meena.p

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Determine the amount of $CaCl_2$ (i = 2.47) dissolved in 2.5 litre of water such that its osmotic pressure is 0.75 atm at 27$^{\large\circ}$ C.

asked Aug 6, 2014 by sreemathi.v

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