Saturday, June 26, 2010

Chemistry Chapter 5 Chemical Bond.

1) a) What are noble gases
b) List down all the noble gases
c) State the electronic configuration of each of the noble gases you mentioned in (b)
d) Why are the noble gases chemically unreactive?

2) The electronic configuration of three element X, Y and Z are shown in Table 1






a) Explain why Z does not react with X and Y




b) X reacts with Y to form a compound with a high melting point. Explain why this is so.




c) i) Suggest the electronic configuration of an element P that will react with X to form a covalent compound with the formula PX4.




ii) Draw the arrangement of electrons in a molecule of this compound




d) State two properties of the compound in (c)




e) State two difference between ionic bond and covalent bond






ESSAY QUESTION



1 a) Using a suitable examples, discuss how the following covalent bonds are formed



i) Double bond



ii) Triple bond [14 m]



b) i) Give two examples f organic solvents



ii) Give one use of two other organic solvents.





2) a) When potassium reacts with an element from Group 17 of the periodic table, a compound is formed. Explain in terms of electron arrangement, why this compound has hight melting and boiling points [ 8m]



b) Describe how covelent bond are formed using HCI as an example [6]

c) Draw the electronic structure of chlorofomr CHCl3 and state the type of bonding involved [3 m]

d) Explain why hydrogen chloride does not conduct electricity when dissolved in chloroform but conduct electicity when dissolved in water [ 3m ]


Biology Chapter 5 Homework


Diagram above shows the nucleus of a somatic cell in an organism.
a) i) State the function of Q
ii) State the component of Q which carries out this function
iii) Draw the components of Q which carry out this function
b) Draw a diagram to show the behaviour of the chromosome during
i) prophase in mitosis
ii) prophase in meiosis
c) i) Name two type of cells produced through meiosis
ii) How many chromosomes are there in each cell named in c (i)?
d) i) What happens if the cell divides out of control during mitosis?
ii) Name two substances that can induce the cell to divide out of control.

Monday, June 21, 2010

Homework Chapter 5 Chemical Bond

1 Table below shows the proton numbers of element W, X, Y and Z (which are not the real symbols of the elements)

Element W X Y Z
Proton No 10 11 17 18

a) Write the electronic configuration of W, X, Y and Z

Element W : ________________
Element X : ________________
Element Y : ________________
Element Z : ________________

b) Which of the element have the stable electronic structures? Explain your answers

c) Element X reacts with element Y to form a compound.
i) Give the molecular formula of the compound form by X and Y

ii) State the type of bonding in the compound formed in (c) i

iii) Give one physical property of the compound

iv) Draw the electronic structure of the particles presend in the compound


Essay Quesion 1
a) When potassium reacts with an element from Group 17 of the Periodic Table, a compound is formed. Explain in terms of electron arrangment, why this compound has high melting and boiling points
b) Describe how covalent bonds are formed using hydrogen and chloride (HCl) as an example.
c) Draw the hydrogen chloride does not conduct electricity when dissolved in chloroform but conducts electricity when dissolved in water.

Essay Question 2
By using suitable example, describe the covalent and ionic bond [14 m]



Pls send the answer next week.

Homework - Chemistry Chapter 13 Heat of Precipitation

An experiment was carried out to determine the heat of precipitation of barium sulphate. 50 cm cube of 1.0 mol dm cube potassium sulphate solution and 50 cm cube of 1.0 mol dm cube barium chloride solution are pured into two separated plastic beakers. The initial temperatures of the solutions are recorded. Then, potassium shulphate solution is quickly poured into the plastic beacker containing barium chloride solution. The mixture is stirred slowly. The results are shown as below

Initial temperature of K2SO4 = 29.5 C
Initial temperature of BaCl2 = 29.5 C

Maximum temperature of the mixture = 34.5 C

a) What is meant by heat of precipitation

b) Write an ionic equation for the reaction

c) State an observation for the experiment

d) i) Calculate the heat chang in the experiment in joules [ Specific heat capacity of solution = 4.2 J/g/C. Density of solution = 1.0 g/cm cube

d) ii) Calculate the number of moles of barium sulphate formed

d) iii) the heat of precipitation of barium shulphate in kJ mol-1

e) Draw the enery profile diagram for the precipitation of barium sulphate

Add Maths Form 5 Chapter 17

1) Find the number of ways of arranging five letters from the work MATHEMATICS in a row. Each arrangment must not contain the letter M.

2) A debating team onsists of 5 students. These 5 students are chosen from 4 monitors, 2 assistant monirots and 6 perfects.
Calculate the number of different ways the tam can be form if
a) there is no restriction
b) the team contains only 1 monitor and exactly 3 perfects

3) Diagram below shows seven letter cards

U N I F O R M

A four letter code is to be formed using four of these cards. Find
a) the number of different four letter code than can be formed
b) the number of different four letter code which end with a consonant


4) A coach want to choose 5 players consisting of 2 boys and 3 girls to form a badminton team. These 5 players are chosen from a group of 4 boys and 5 girls
Find
a) the number of ways the team can be formed
b) the number of ways the team members can be arranged in a row gor a group photograph, if the three girls sits next to each other.


5) Digram below shows six numbered cards
3 5 6 7 8 9

A four digit number is to be formed by using four of these cards
How many
a) different numbers can be formed
b) differnt odd number can be formed.