The process of coating iron or steel with zinc is known as:
The empirical formula of certain compound in CH3. Its molar mass is 30 g. What will be its molecular formular?
The simplest formula of a compound formed when combining 36 g of magnesium and 14 g of nitrogen is:
What is the oxidation state of Chlorine in KCIO3?
The simplest formula of a compound formed when combining 13g of aluminum and 17g of chlorine is:
Which net charge exists in radicals?
What is the IUPAC name for H2S04 ?
How many atoms are there in a water molecule
Carbon has two main isotopes, 12 C and 14 C with relative abundance of 98.89% and 1.11% respectively. Calculate the relative atomic mass of carbon.
In the formula of the compound F2K3 the valences of F and K are respectively:
Given that, element “M” with electronic configuration of 2:8:3 combines with element “G” with electronic configuration of 2:6 to form a compound; What is the chemical formula of the compound formed.
A covalent bond is formed when
The pair elements which is most likely to form a covalent bond when they react together is:
A calcium ion (Ca2+) differs from calcium atom (Ca) because a calcium ion has:
(b) An organic compound P consist of 52.2% of carbon, 13% of hydrogen and 34.8% of oxygen. The vapour density of P is 23. Calculate the molecular formula of the compound P and write possible isomer(s) from the molecular formula determined.
View Ans(c) Sodium is a solid while chlorine is a gas at room temperature although they are in the same period in the periodic table. What is the cause of this difference? (3 marks)
View Ans(b) What is the oxidation number of iron in iron (III) chloride? (3 marks)
View Ans7. (a) Differentiate empirical formula from molecular formula. (2 marks)
View Ans(b) Calculate the percentage composition by mass of water in a hydrated magnesium chloride MgCl2•6H 2O. (3 marks)
View Ans(c) Calculate the empirical formula for a compound with the following composition: lead 8.32 g, sulphur 1.28 g, oxygen 2.56 g (relative atomic wt of lead = 207, sulphur = 32, oxygen = 16) (5 marks)
View Ans(b) Write down the formulae of the simplest compounds you would expect when
(i) A and B combine chemically
(ii) C and D combine chemically. (2 marks)
View Ans(c) (i) What types of bonding you would expect to occur in each of the compounds formed in (b)
(ii) List three (3) differences in properties you would expect to find between the compounds in (i) as a result of their difference in types of bonding. (4 marks)
View Ans9. A certain gaseous compound contains 30.4% of nitrogen and 69.6% of oxygen by mass. If the molar mass of the compound is 92, calculate its molecular formula.
Stage | Nitrogen | Oxygen
|
………………… ………………… ………………
………………… …………………… ……………
…………………… …………………… …………
View Ans(a) A Form IV student was asked to react phosphate ion and sodium ion forming compound W. Suggest the IUPAC name of W and find the oxidation state of phosphorous in W.
(b) Calculate the percentage composition of lead in the compound Pb(N03)2. (7 marks)
View Ans10.(a) Define the following terms:
(i)Valency
(ii)Oxidation state
(iii) Anion
(iv)Cation
(b) Calculate the oxidation state of the underlined elements in the following radicals:
(i) NH4+
(ii) SO42+
(iii) CLO3-
(c) A compound consists of 40% carbon, 6.67% hydrogen and 53.33% oxygen. If its relative molecular mass is 60, calculate the following:
(i)Empirical formula
(ii)Molecular formula
View Ansgive the IUPAC name of the compound. (7 marks)
View Ans10.. (a) The diagram below shows the bonding between two elements A and B.
(i)Write the valence of B.
(ii)Identify the valence of A.
(iii)State the type of bonding formed between A and B.
(iv)Write the formula of the compound formed by A and B.
(b) Write the formula of the compound formed by the combination of:
(i) NH4+ and SO 2-
(c)State the number of atoms of each element in CaCl2.
(d)Calculate the oxidation state of sulphur in SO 2-.