tutorial chapter 1: solutions

chapter 1

1.		Sodium hydrogen carbonate is prepared from NaCl and ammonium hydrogen carbonate, according to equation: NH4HCO3(aq)  +  NaCl (aq)    ®  NaHCO3 (aq)  +  NH4Cl (aq) If 0.3 mol NH4HCO3 are reacted with 0.2567 mol of NaCl, how many grams of NaHCO3 are obtained?
2.		CH4 (g)  +  H2O (g)  ®  3H2 (g)  +  CO (g) What mass of H2O is required to react exactly with 249 g of methane?
3.		Suppose 25.0 kg of nitrogen gas and 5.00 kg of hydrogen gas are mixed and reacted to form ammonia. Calculate the mass of ammonia produced when this reaction is run to completion.
4.		Balance these two equations below:
	a)	Na   +   H2O   ­®   NaOH   +   H2
	b)	NH4OH   +   H2SO4   ­®   (NH4)2SO4   +   H2O
5.		When aluminium metal is exposed to air, a protective layer of aluminium oxide (Al2O3) forms on its surface. This layer prevents further reaction between aluminium and oxygen, and it is the reason that aluminium beverage cans do not corrode. [in the case of iron, the rust or the iron(III) oxide, that forms is too porous to protect the iron metal underneath, so rusting continues]. Write a balanced equation for the formation of Al2O3
6.		Balance the equation representing the reaction between iron(III) oxide, Fe2O3, and carbon monoxide (CO) to yield iron (Fe) and carbon dioxide (CO2)
7.		Balance the following equations.
	a)	NaOH   +   H2SO4   ­®   Na2SO4   +   H2O
	b)	N2O5   ­®   N2O4   ­®   O2
8.		Urea [(NH2)2CO] is prepared by reacting ammonia with carbon dioxide: 2NH3 (g)   +   CO2 (g)   ­®   (NH2)2CO (aq)   +   H2O (l) In one process, 637.2 g of NH3 are treated with 1142 g of CO2.
	a)	Which of the two reactants is the limiting reagent?
	b)	Calculate the mass of (NH2)2CO formed.
	c)	How much excess reagent (in grams) is left at the end of the reaction?

Tutorial - Chemical Kinetics

Chemical Kinetics

First – Order Reaction

1.       The conversion of cyclopropane to propene in the gas phase is a first – order reaction with a rate constant of 6.7 x 10^-4 s^-1 at 500 °C.

®     ­       CH3  -  CH  =CH2

a.       If the initial [ ] of cyclopropane was 0.25 M, what is the [ ] after 8.8 min?

b.      How long (in minutes) will it take for the concentration of cyclopropane to decrease from 0.25 M to 0.15 M?

c.       How long (in minutes) will it take to convert 74 % of the starting material?

Half - time

1.       The decomposition of ethane, C₂H₆ to methyl radicals is first order reaction with a rate constant of 5.36 x 10^-4 s^-1 at 700 °C:

C₂H₆ (g)   ­®   2CH₃

Calculate the half life of the reaction in minutes.

2.       Rate of reaction  A  +  B  ­®  Products is given as a functional of different initial [ ] of A and B. 

[A] (mol/L)	[B] (mol/L)	Initial rate (mol/L/min)
0.01	0.01	0.005
0.02	0.01	0.010
0.01	0.02	0.005

a.       Determine the order of reaction with respect to A and with respect to B.

b.      What is the half life of A in the reaction.

3.       Propane, C₃H₈, burns in oxygen to give carbon dioxide and water. If the concentrations of propane decrease at a rate of 0.30 Ms^-1, what is the rate at which the concentration of oxygen is decreasing? Determine also the rate of increase in concentration of all the products.

4.       Consider the reaction

4NO₂(g)    +    O₂(g)    ®    2N₂O₅(g)   

Suppose that, at a particular moment during the reaction, molecular oxygen is reacting at the rate of 0.0024 M/s.

a)         At what rate is N₂O₅ being formed?

b)      At what rate is NO₂ reacting?

5.       The reaction of nitric oxide with hydrogen at 1280 °C is

2NO (g)    +    2H₂ (g)    ­®    N₂ (g)    +    2H₂O (g)

From the following data collected at this temperature, determine :

a)      The rate law

b)      The rate constant

c)       The rate of the reaction when [NO] = 12.0 x 10^-3 M and [H₂] = 6.0 x 10^-3 M

Experiment	[NO] (M)	[H2] (M)	Initial rate (M/s)
1	5.0 x 10-3	2.0 x 10-3	1.3 x 10-3
2	10.0 x 10-3	2.0 x 10-3	5.0 x 10-3
3	10.0 x 10-3	4.0 x 10-3	10.0 x 10-3

6.       The following reaction

H₂SeO₃    +    6I^-    +    4H⁺    ­®    Se    +    2I₃^-    +    3H₂O

Has the rate law: rate  =  k[H₂SeO₃ ] [I^-  ]³ [H⁺]²

Answer the following questions based on the rate law above.

a)      What is the order of the reaction with respect to each reactant?

b)      What is the overall order of the reaction?

c)       What are the units of the rate constant, k?

8.		The following data were collected for the reaction A  +  B  ­®  C  +  D Experiment Initial concentration of A (M) Initial concentration of B (M) Initial rate of formation of C (Ms-1) 1 010 0.10 1.2 x 10-3 2 0.10 0.20 2.4 x 10-3 3 0.20 0.10 4.8 x 10-3 Determine the rate order of reaction and calculate its rate constant. Following that, write the rate law for the reaction.
9.	(a)	Consider the reaction  A à  B. The rate of the reaction is 1.6x10-2 Ms-1 when the concentration of A is 0.35 M. Calculate the rate constant, k if the reaction is (i)                 First order in A (ii)               Second order in A
	(b)	(i)       Define the half-life of a reaction. (ii)     Write the equation relating the half life of a first order of reaction to the rate constant, k. (iii)   Determine the half life of a compound if 75 % of a given sample of the compound decomposes in 60 min. Assume first order kinetics.
	(c)	The rate constant for a second order reaction 2NO2 (g)  à  2NO (g)  +  O2 (g) is 0.54 M-1s-1 at 300 °C. How long (in second) would it take for the concentration of NO2 to decrease from 0.562 M to 0.128 M.

SAHABAT

Asslamualaikum.

Bukan mudah mencari sahabat yang baik. Dan bukan mudah untuk kita mendapat sahabat  yang baik. Untuk mendapat yang terbaik, seharusnya, kita perbaiki diri untuk menjadi lebih baik dan menjadi seorang sahabat yang baik. Dan untuk memperbaiki diri ke arah kebaikan, perlulah kita mencari sahabat yang baik. Macam mana tu?? Macam confuse je..

Mencari sahabat yang baik adalah penting dalam kehidupan kita seharian. Apabila kita tersalah langkah dalam memilih sahabat, haluan hidup kita juga akan mudah hanyut.

Sahabat yang baik akan sentiasa mengingatkan kita ke jalan yang benar. Sahabat yang baik tidak akan mengumpat di belakang kita. Sahabat yang baik juga tidak akan mempengaruhi kita untuk membuat sesuatu yang salah. Dan sebaliknya sahabat yang baik akan mengajak kita untuk berusaha bersama ke arah kejayaan.

Selamat menjadi seorang sahabat yang terbaik kepada sahabat anda..

P/s: Kenapa saya bercerita tentang sahabat?? Kerana ramai di antara kita telah hanyut dan leka kerana mempunyai sahabat yang membawa ke arah kegagalan..

Tetapkan matlamat diri untuk berjaya dengan cemerlang dan tepislah segala godaan yang membawa anda kepada kehancuran akhlak. 

Perhatian untuk semua pelajar DAS12703

Semua pelajar DAS12703,

Class pada 10 December 2012 akan dibatalkan kerana semua pelajar DAS12703 adalah diwajibkan untuk menghadiri program “UNESCO INTERNATIONAL DAY FOR PEACE AND DEVELOPMENT”.

Tarikh: 10 Disember 2012

Masa: 8.30 pagi hingga 1.00 tengahari

Tempat: Dewan Tunku Ismail Ibrahim (DTII)

Kehadiran adalah DIWAJIBKAN

Anda juga digalakkan untuk menyertai pertandingan pameran (berbentuk poster) yang bersesuaian dengan tema program INTERNATIONAL DAY FOR PEACE AND DEVELOPMENT.

Terima kasih dan harap maklum. 

Tuan/Puan,

PERTANDINGAN POSTER SEMPENA PROGRAM “UNESCO INTERNATIONAL SCIENCE DAY FOR PEACE AND DEVELOPMENT“ ANJURAN PPD DAN FSTPi

Dengan segala hormatnya saya merujuk kepada perkara di atas.

2.        Sukacita dimaklumkan Pusat Pengajian Diploma (PPD) dan Fakulti Sains, Teknologi dan Pembangunan Insan (FSTPi) akan menganjurkan Program “UNESCO International Science Day For Peace and Development“ seperti ketetapan berikut:

Tarikh        :        10 Disember 2012 (Isnin)
Masa                :        8.30 pagi hingga 1.00 tengahari
Tempat        :        Dewan Tunku Ismail Ibrahim UTHM
Peserta        :       Terbuka kepada pelajar PPD dan FSTPi
Tema        :        Science for Peace and Development

3. Syarat-syarat penyertaan adalah seperti berikut:

i. Terbuka kepada pelajar-pelajar PPD dan FSTPi.
ii. Boleh dilukis tangan atau direka menggunakan komputer.
iii. Bersaiz kertas lukisan atau A3.
iv. Penyertaan perlu dihantar selewat-lewatnya pada hari Isnin 10 Disember 2012 jam 8:15 pagi di meja urusetia Dewan DTII.
v. Butiran peserta perlu disertakan di belakang poster masing-masing.
vi. Boleh disertai secara individu atau berkumpulan (maksimum 3 orang).

4. Sehubungan itu, diminta pensyarah-pensyarah yang mengajar kuliah dan penasihat-penasihat akademik menggalakkan pelajar untuk menyertai pertandingan ini. Hadiah disediakan untuk tiga (3) penyertaan terbaik. Segala perhatian serta kerjasama yang diberikan amatlah dihargai dan didahului dengan ucapan terima kasih.
 
Sekian.