Answer all the questions in the spaces provided.
- The set up below can be used to prepare oxygen gas. Study it and answer the questions that
- Identify substance X.1mk
- What property of oxygen makes it possible for it to be collected as shown in the above
set up? 1mk
- State two uses of oxygen. 2kms
- Describe an experimental procedure that can be used to extract oil from nut seeds.3mks
- In terms of structure and bonding, explain the following observations:
- The melting point of water H2O is higher than that of H2S. 2mks
- Melting point of chlorine is lower than that of sulphur. 2mks
- a. Define the term salt. 1mk
b.Apart from direct synthesis name two other methods of salt preparation. 2mks
c.The diagram below illustrates a method of preparing salts by direct synthesis.
d.This method can be used to prepare either aluminum chloride or iron (III) chloride.
e.What is the purpose of anhydrous calcium chloride? 1mk
- Define the following terms. 3mks
- Normal salt
- Efflorescent salts
- Deliquescent salts
- a. What is meant by an allotrope? 1mk
b.Give two allotropes of carbon. 2mks
- The grid below is part of the periodic table. Use it answer the questions that follow. (The letters are not the actual symbols of the elements).
- Which is the most reactive non-metallic element shown in the table? Explain. (2 mks)
- (i) Write the formula of the compound formed when element A reacts with element B. (1 mk)
(ii) Name the bond type in the compound formed in b (i) above. (1 mk)
- (i) What is the name given to the group of elements where C, G and H belong? (1 mk)
- The melting points of elements F and G are 1410 C and -101 C respectively. In terms of structure and bonding, explain why there is a large difference in the melting points of F and G. (2 marks)
- D forms two oxides. Write the formula of each of two oxides. (1 mark)
- J is an element that belongs to the 3rd period of the periodic table and is a member of the alkaline earth elements. Show the position of J in the grid. (1 mark)
- i) Define the term isotope.1mk
ii) The table below gives the number of electrons, protons and neutrons in substances X, Y and Z Study it and answers the questions that follow.
|X||10||10 8||10 10|
- Which letter represents an ion? (1 mark)
- Which of the substances are isotopes? Give a reason. (2 marks
- Show the electron arrangement of Y 1mk
- a. What is an impurity? 1mk
b .The curve below represents the variation of temperature with time when pure and
Impure samples of a solid were heated separately.
Which curve sows the variation in temperature for the pure solid? Explain.2mks
- The diagram below shows the physical state of matter. Study it and answer the questions that follow.
- Identify the processes R, V, w and U. 4mks
- Name the process S and T. 1mk
- Name two substances which can undergo the process represented by S and T. 2mks
- Define the term ionization energy. 1mk
- The table below gives the energy required to remove the outermost electron for some group I elements.
|Ionization Energy kJmol-1||494||418||519||376|
Arrange the elements in order of their reactivity starting with the most reactive. 2mks
- The table below shows some properties of substances C,D and E. Study it and answer the questions that follow.
|Substance||M.P (0C)||Solubility in water||Electrical solid state||Conductivity molten stated|
- With a giant molecular structure. 1mk
- That has ionic bonding. 1mk
- That is a metal. 1mk
- An element Y has the electronic configuration 2.8.5
- Which period and group of the periodic table does the element belong? 2mks
- Write electron arrangement of the ion of Y. 1mk
c) Explain the difference between the atomic radium of element Y and
its ionic radius. 2mks
- The table below shows the PH values of solutions I, II, III and IV.
- Which solution is likely to be that of: 3mks
- Calcium hydroxide
- Sodium chloride
- Potassium hydroxide
- a. What is the chemical name for rust? 1mk
b.State three conditions necessary for rusting. 3mks
c. State tree methods of preventing rusting. 3mks
- Write an equation to show the effect of heat on: 3mks
- Zn (NO3)2