Recent questions in Chemistry

Which of the following elements is not the constituent of zeolite A

asked Jul 25, 2014 by sreemathi.v

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Which of the following statements is correct?

asked Jul 25, 2014 by sreemathi.v

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Which of the following bonds has the highest bond energy ?

asked Jul 25, 2014 by sreemathi.v

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A certain reaction is first order, and 540 s after initiation of the reaction, 32.5% of the reactant remains. At what time after initiation of the reaction of the reaction will 10% of the reactant remain?

asked Jul 25, 2014 by balaji.thirumalai

1 answer

Which of the following is an allylide?

asked Jul 25, 2014 by sreemathi.v

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A certain first order reaction is 45% complete in 65 seconds. Determine the rate constant and the half-life for this process.

asked Jul 25, 2014 by balaji.thirumalai

1 answer

Calculate half-life for first-order reaction if 68% of a substance is reacted within 66 s.

asked Jul 25, 2014 by balaji.thirumalai

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Which of the following is a acetylide?

asked Jul 25, 2014 by sreemathi.v

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Which of the following is a methanide?

asked Jul 25, 2014 by sreemathi.v

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What is the rate of a reaction if $[A]_o = 560\;M$, $[B]_o = 0.2\;M$, and 2nd order rate constant is $0.1\;M^{-1}s^{-1}$?

asked Jul 25, 2014 by balaji.thirumalai

1 answer

What is the concentration of $A$ at time $45\;s$ if $[A]_o = 1\;M$, $[B]_o = 45\;M$, and 2nd order rate constant is $0.6\;M^{-1}s^{-1}$?

asked Jul 25, 2014 by balaji.thirumalai

1 answer

Which of the following compounds of lead is the most stable?

asked Jul 25, 2014 by sreemathi.v

1 answer

If $[A] = 55\;M$ at $39s$, $[A]_o = 99\;M$, and $[B]_o = 1000\;M$, what is the 2nd order reaction rate constant?

asked Jul 25, 2014 by balaji.thirumalai

1 answer

Which of the following fuel gases has the highest calorific value?

asked Jul 25, 2014 by sreemathi.v

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Hydrolysis of $SiF_4$ in alkaline medium produces

asked Jul 25, 2014 by sreemathi.v

1 answer

Amongst the following element,which one has the highest melting point?

asked Jul 25, 2014 by sreemathi.v

1 answer

Lead pencil contains

asked Jul 25, 2014 by sreemathi.v

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Bond energy is highest amongst

asked Jul 25, 2014 by sreemathi.v

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Which of the following oxides is used in lead accumulators?

asked Jul 25, 2014 by sreemathi.v

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The only stable tetrahalide of lead is

asked Jul 25, 2014 by sreemathi.v

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Which of the following statements is not correct?

asked Jul 25, 2014 by sreemathi.v

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Which of the following statements is not correct?

asked Jul 25, 2014 by sreemathi.v

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Heating lead in air at higher temperature ($T \geq 725K)$,the oxide formed is

asked Jul 25, 2014 by sreemathi.v

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Which of the following equations is not actually observed?

asked Jul 25, 2014 by sreemathi.v

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In the purification of lead electrolytically,which of the following facts is not correct?

asked Jul 25, 2014 by sreemathi.v

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The chief ore of lead is

asked Jul 25, 2014 by sreemathi.v

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Which is the chief ore of tin?

asked Jul 25, 2014 by sreemathi.v

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Which of the following is not correct?

asked Jul 25, 2014 by sreemathi.v

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Which of the following statements regarding glass is not true?

asked Jul 25, 2014 by sreemathi.v

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The rate constant for the 2nd order reaction shown below is $0.54 M^{–1}$ at 300$^{\circ}$ C. How many seconds would it take for the concentration of NO$_s$ to decrease from $0.62\; M$ to $0.28\; M$?

asked Jul 24, 2014 by balaji.thirumalai

1 answer

The thermal decomposition of phosphine to phosphorus and hydrogen gas is a first order reaction, with a half-life of 35 s at 680$^\circ$C. Calculate the time required for 95% of phosphine to decompose.

asked Jul 24, 2014 by balaji.thirumalai

1 answer

The thermal decomposition of N$_2$O$_5$ to form NO$_2$ and O$_2$ is a first order reaction. The rate constant for the reaction is $5.1x10^{–4}s^{-1}$ at $318^{\circ} K$. Calculate the half-life of this reaction.

asked Jul 24, 2014 by balaji.thirumalai

1 answer

The following data was collected in three different experiments:

asked Jul 24, 2014 by balaji.thirumalai

1 answer

Calculate the value of k for this reaction based on the following data collected in three different experiments:

asked Jul 24, 2014 by balaji.thirumalai

1 answer

Consider the following reaction:$ A + 3 B \rightarrow 2 C + 2 D$. In one experiment, the rate of change of B was found to be $2.50 \times 10^{–4}\;M/s$. What is the rate of change of C in this experiment?

asked Jul 24, 2014 by balaji.thirumalai

1 answer

A certain first order reaction proceeds through t first order kinetics. The half-life of the reaction is 180 s. What percent of the initial concentration remains after 900s?

asked Jul 24, 2014 by balaji.thirumalai

1 answer

The decomposition of $N_2O_5$ is given by the following equation: $2\; N_2O_5\; (g) \rightarrow 4 NO_2\;(g) + O_2\;(g)$ At an initial $[N_2O_5]_0 = 3.15\; M$, the initial rate of reaction is $5.45 \times 10^{-5} \;M/s$ and when $[N_2O_5]_0 = 0.78\; M$, the initial rate of reaction is $1.35 \times 10^{-5}\; M/s$. What is the rate constant of this reaction?

asked Jul 24, 2014 by balaji.thirumalai

1 answer

The reaction $A \rightarrow \text{Products}$ is second order in $A$. Initially $[A]_0 = 1.00 M$ and after $25 \; \text{mins}, \;[A] = 0.25\; M$. What is the rate constant for this reaction?

asked Jul 24, 2014 by balaji.thirumalai

1 answer

From the integrated rate law for a first order reaction, $ [A] = [A]_0\; e^{-kt}$. Suppose rate constant, $k = 2.95 X 10^{-3} s^{-1}$, What percent of $A$ remains after $150 \;s$?

asked Jul 24, 2014 by balaji.thirumalai

1 answer

An elementary reaction, $2 A + C \rightarrow D$ , is second order in $A$ and first order in $C$. The rate of this reaction is $2.5 \times 10 ^{-1}1\; M/s$ when the concentrations of $A$ and $C$ are all $3.00\; mM$. What is the rate constant for the reaction?

asked Jul 24, 2014 by balaji.thirumalai

1 answer

A first order reaction has a rate constant of $1.00\;s^{-1}$. What is the half life of the reaction?

asked Jul 24, 2014 by balaji.thirumalai

1 answer

Which of the following statements is not correct?

asked Jul 24, 2014 by sreemathi.v

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Which of the following statements is not correct?

asked Jul 24, 2014 by sreemathi.v

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Which of the following statements is not correct ?

asked Jul 24, 2014 by thanvigandhi_1

1 answer

The dissolution of stannous hydroxide in excess base produces

asked Jul 24, 2014 by sreemathi.v

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Which of the following statements is not correct?

asked Jul 24, 2014 by sreemathi.v

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Which of the following facts is not correct ?

asked Jul 24, 2014 by thanvigandhi_1

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Which of the following oxides is an acidic oxide?

asked Jul 24, 2014 by sreemathi.v

1 answer

Which of the following statements is not true ?

asked Jul 24, 2014 by thanvigandhi_1

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Which of the following statements is not correct?

asked Jul 24, 2014 by sreemathi.v

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