Consider a certain reaction A → Products with k = 2.0 x 10-2 s-1. Calculate the concentration of A remaining after 100 s if the initial concentration of A is 1.0 mol L-1.
k= 2.0 × 110-2 s-1
T= 100 s
[A]o= 1.0 moL - 1
Since the unit of kis s - 1, the given reaction is a first order reaction.
Therefore, k = 2.303/t Log [A]º / [A]
⇒2.0 × 110-2 s-1 = 2.303/100s Log 1.0 / [A]
⇒2.0 × 110-2 s-1 = 2.303/100s ( - Log [A] )
⇒ - Log [A] = - (2.0 x 10-2 x 100) / 2.303
⇒ [A] = antilog [- (2.0 x 10-2 x 100) / 2.303]
= 0.135 mol L - 1 (approximately)
Hence, the remaining concentration of A is 0.135 mol L - 1.
The half-life for radioactive decay of 14C is 5730 years. An archaeological artifact containing wood had only 80% of the 14C found in a living tree. Estimate the age of the sample.
For a first order reaction, show that time required for 99% completion is twice the time required for the completion of 90% of reaction.
The rate of a reaction quadruples when the temperature changes from 293 K to 313 K. Calculate the energy of activation of the reaction assuming that it does not change with temperature.
A first order reaction takes 40 min for 30% decomposition. Calculate t1/2.
In a reaction, 2A → Products, the concentration of A decreases from 0.5 mol L-1 to 0.4 mol L-1 in 10 minutes. Calculate the rate during this interval?
The conversion of molecules X to Y follows second order kinetics. If concentration of X is increased to three times how will it affect the rate of formation of Y?
During nuclear explosion, one of the products is 90Sr with half-life of 28.1 years. If 1μg of 90Sr was absorbed in the bones of a newly born baby instead of calcium, how much of it will remain after 10 years and 60 years if it is not lost metabolically.
Sucrose decomposes in acid solution into glucose and fructose according to the first order rate law, with t1/2 = 3.00 hours. What fraction of sample of sucrose remains after 8 hours?
For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.
The decomposition of A into product has value of k as 4.5 x 103 s-1 at 10°C and energy of activation 60 kJ mol-1. At what temperature would k be 1.5 x 104 s-1?
Write the formulas for the following coordination compounds:
(i) Tetraamminediaquacobalt (III) chloride
(ii) Potassium tetracyanonickelate(II)
(iii) Tris(ethane-1,2-diamine) chromium(III) chloride
(iv) Amminebromidochloridonitrito-N-platinate(II)
(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate
(vi) Iron(III) hexacyanoferrate(II)
(i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N
(ii) Write IUPAC names of all the isomers.
(iii) What type of isomerism is exhibited by different pairs of amines?
Why are solids rigid?
Write any two characteristics of Chemisorption.
Write the structures of the following compounds.
(i) α-Methoxypropionaldehyde
(ii) 3-Hydroxybutanal
(iii) 2-Hydroxycyclopentane carbaldehyde
(iv) 4-Oxopentanal
(v) Di-sec-butyl ketone
(vi) 4-Fluoroacetophenone
Which of the ores mentioned in Table 6.1 can be concentrated by magnetic separation method?
Why are pentahalides more covalent than trihalides?
Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?
Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.
Write structures of the following compounds:
(i) 2-Chloro-3-methylpentane
(ii) 1-Chloro-4-ethylcyclohexane
(iii) 4-tert. Butyl-3-iodoheptane
(iv) 1,4-Dibromobut-2-ene
(v) 1-Bromo-4-sec. butyl-2-methylbenzene
Write the structures of products of the following reactions;
(i)
(ii)
(iii)
(iv)
[NiCl4]2- is paramagnetic while [Ni(CO)4] is diamagnetic though both are tetrahedral. Why?
Explain why fluorine forms only one oxoacid, HOF.
State the role of silica in the metallurgy of copper.
Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.
Giving examples, differentiate between 'roasting' and 'calcination'.
Illustrate with examples the limitations of Williamson synthesis for the preparation of certain types of ethers.
How are vitamins classified? Name the vitamin responsible for thecoagulation of blood.
Mention three areas in which H2SO4 plays an important role.
Write a balanced equation for the hydrolytic reaction of PCl5 in heavy water.