What are The Basic Things to Know in Chemistry?

What are the basic things to know in Chemistry? This is a common question asked by so many students. i have pulled answers to some interesting chemistry questions.

1. State differences between metals and non-metals

Metals are lustrous
Metals are malleable, ductile and sonorous
Metals have high densities               
Good conductors of heat/electricity Metals are reducing agents Metals tend to form ionic compounds
Non-metals are non-lustrous
Non-metals are not malleable, ductile and sonorous
Non-metals have low densities
Poor conductors of heat /electricity Non-metals are oxidizing agents Non-metals form covalent compounds

2. State differences between mixtures and compounds 

Maybe homogeneous or heterogeneous Constituents are not chemically bound together
Constituents can be added in any ratio
The Properties of a mixture are the sum of the individual constituents
Always homogeneous  
Component elements are chemically bound together Components are present in a fixed ratio
The properties of a compound differ entirely from those of its component  elements

3. State differences between a physical change and chemical change 

Easily reversible No new substance has formed
No change in the mass of substances involved
Does not involve any great heat change
Not easily reversible
New substances formed Change in the mass of substances involved
Involves great heat change

4. Mention two Criteria for purity of a substance

    a. fixed melting and boiling point       

    b. A single spot on a chromatogram (colored substance)

5. Mention 3 factors that affect solubility of a solid (salt)

   a. Temperature      b. nature of solvent            c. size of the particle

6. Mention the physical properties on which these separation methods depend on

Separation methodsPhysical property
Filtration / Decantation  
The difference in particle size
Difference in boiling points
Ability of a substance to sublime  
Insoluble solid in water    

7. State the contributions of the following scientists

John Dalton
J.J Thomson  
Ernest Rutherford
Niels Bohr
James Chadwick
Erwin schrodinger Dmitriv mendeleev Moseley
Billiard ball
Electron and proton(plum pudding model)
Nucleus Energy l
evels/shells/orbits/quanta Neutron Electron cloud
Periodic table
Atomic number


8.  State three statements of Dalton’s atomic theory    

Statements of Dalton’s atomic theory
Atom cannot be created nor destroyed
elements are made up of small indivisible particles called atoms
When atoms react, they do so in simple ratio
Atoms of an element look alike and differ from atoms of other elements

9. State three modifications of Dalton’s atomic theory

Modifications of Dalton’s atomic theory
Isotopy-atoms of the same element do not always look alike
Nuclear reaction: during nuclear reactions, atoms can be created or destroyed
Macromolecules/starch: in macromolecules atoms are not  combined in simple ratios

10. State three properties of ionic compound/electrovalent compounds

Ionic compounds/electrovalent compounds Ionic compounds have high melting and boiling points They are soluble in water
They conduct electricity in molten or aqueous form they are usually solids at room temperature

11. State three properties of covalent compounds

Covalent compounds Covalent compounds have low melting and boiling pointsCovalent compounds are not soluble in water but soluble in non-polar solvents they do not conduct electricity They are usually volatile liquids or gases at room temperature

12. State three assumptions or statements of kinetic theory of gases

Assumptions of kinetic theory of gases The gas molecules move randomly in a straight lineThe collisions of the gas molecules are perfectly
The actual volume occupied by the gas molecules themselves is negligible compared to the actual volume of the container.
Cohesive forces between the gas molecules are negligible
The temperature of the gas is a measure of the average kinetic energy of the gas particles

13. State  3 uses of diamond

Uses of DiamondReasons behind the uses
Used as drills for mining
Used as abrasives to sharpen other tools
Used in cutting glass and metals
Used in making jewellery
Used as pivots in precision instruments
Because it is hard and dense  
Because it is hard and dense  
Because it is hard and dense  
Because it has a high refractive index and dispersion power
Because it is hard and dense

14. State the uses of graphite

Uses of graphiteReasons behind the uses
Used as an excellent dry lubricant
Good conductor of electricity
Used as electrodes in electrolytic cells and electroplating
Used to line crucibles
Used as pencil leads Used as pigment in paints
Layers can slide over another easily  
Presence of mobile electrons  
Inert and conducts electricity    
Withstand high temperature
Marks paper and can mix with clay Black color

15.Mention 4 components of destructive distillation of coal   

Components of coalUses
Ammoniacal liquor
Coal tar    
Coal gas
Used as Fuel
Used in making Fertilizer
Making chemicals e.g Paints, dyes,insecticides,drugs and explosives
Used as a Gaseous fuel

16. State 4 periodic properties

Periodic properties
ionization energy Electron affinity Electronegativity/electropositivity Atomic radius Melting and boiling point

17. State three factors that govern the periodic properties      

Size of nuclear charge
Distance of outermost electron from the nucleus
Shielding effect/screening effect

18.State three factors that affect preferential discharge of ions during electrolysis  

1. Position of ion in the electrochemical series
2. Nature of electrode 3. concentration of ions

18. State three applications of electrolysis

1. Extraction of elements
2. Purification of metals
3. Electroplating of one metal by another
4. Preparation of certain important compounds  like NaOH etc

19. State three factors that emf of a cell depends on.     

The emf of a cell depend on Concentration of ionsTemperatureDistance between the two ions in the electrochemical series

20. Mention two functions of the salt bridge

1. Salt bridge connects two half cells
2. a channel for the exchange of ions
3. it completes the circuit

21. State two differences between primary cell and secondary cells 

Primary cellsSecondary cells
Cannot be recharged    
High internal resistance  
Irreversible reaction  
Can be recharged and reused  
Low internal resistance  
Reversible reaction  

22.  Give two examples of primary cells and two examples of secondary cells

Primary cellsSecondary cells
Daniel cell Leclanche cellLead-acid accumulator Nickel-iron (Ni-Fe) cell  

23.state two conditions for spontaneity of a reaction

Positive entropy, low enthalpy Free Gibbs energy must be negative

24. state six factors that affect rate of a reaction

1. Temperature
2. Nature of reactants
3. Surface area 4. Concentration /pressure for gases 5. Presence of light 6. Presence of a catalyst

25. State the three factors that influence or govern the factors affecting the rate of reaction

Energy content of the particles Frequency of collisions Activation energy of the particles

25. state the factor that affects equilibrium constant


26. State three applications of solubility curves  

1. Enables pharmacists to determine the amount of solid drugs  that must be dissolved in a given solvent 2. Enables chemists and researchers to determine the most suitable solvents to be used at different temperatures for extraction of chemicals 3. Applied in separating or purifying mixtures

27. State three factors that affect equilibrium or rate of attaining equilibrium 

1. Temperature 2. Pressure 3. Concentration

28. State four properties of a system in equilibrium     

1. A chemical system can only be achieved in a closed system
2. A chemical equilibrium has both the forward and backward reaction
3. A chemical equilibrium is dynamic in nature(concentrations of reactants and product remain constant)
4. A catalyst may be used to alter the time required to attain equilibrium  

29. State the four quantum numbers and their effects

Principal quantum number Azimuthal quantum number Magnetic quantum number Spin quantum number

30. state the optimum conditions for ammonia production/Haber process  

Temperature of 4500C Pressure of 200 atm Finely divided iron as catalyst

31. state the optimum conditions for sulphuric acid production/contact process

The temperature of 4500C Pressure of 1 atm Vanadium V oxide (V2O5) as catalyst

32. State two differences between burning and rusting

1. Rusting is a slow process while burning is a rapid process
2. water is required for rusting while burning hardly take place in the presence of water
3. Heat given in rusting is small while the heat given out in burning is much
4. Rusting involves iron while burning may not  

33. State the similarities between rusting and burning

1. Both are oxidation processes because they need oxygen 2. Both give out heat  

34. State the effects of temporary hardness

Furring of kettles and boilers Stalagmites and stalactites

35. State the advantages of hard water

1. Hard water tastes better
2. Builds strong teeth in children
3. Hard water helps animals such as snails and crabs to make their shells
4. Hard water can be supplied in pipes made of lead

36. State two disadvantages of hard water

1. Hard water wastes a lot of soap
2. hard water causes furring of kettles and boilers
3, Hard water cannot be used in dyeing and tanning  

37.Mention two properties of water

1. Boiling point of 1000C
2. Freezing point of o0C
3. Colorless, odourless and tatsteless
4. Density of 1 g/dm3 at 250C

38. State the solubility rule   

Solubility rule
All salts of K, Na, NH4+ are soluble
All nitrates are solubleAll sulphates are soluble except BaSO4, PbSO4, CaSO4
All chlorides, iodides and bromides are soluble except AgCl,AgI,AgBr, PbCl2, PbBr2, PbI2,
All sulphides, hydroxides and carbonates are insoluble except K2CO3, K2S, KOH, Na2CO3,NaOH, Na2S

39. state two differences between the colloidal solutions and true solutions

True solutionsColloidal solutions
Solution can be dialyzed Solution do not scatter lightCannot be dialyzed Solution scatter light

40. State the common solutes and common solvents

Tincture of iodine
Soda water  
Ethanol in water
Iodine dissolved in ethanol
Carbon IV oxide dissolved in water  

41. Give two examples of polar and non-polar molecules

Polar moleculesNon-polar molecules
Water Trichloromethane Ammonia All ionic compoundsBenzene, normal alkanes

42. Mention three instruments used in detecting radiations

Scintillation counter Diffusion cloud chamber Geiger Muller counter

43. uses of common radioisotopes

1. Iodine 131 used in treating thyroid disorder 2. Uranium 235 used in making nuclear fuel 3. cobalt 60 4. carbon 14 used in archeology for dating 5  cobalt 60 used in cancer treatment 6. Nickel 63 used to detect explosives

44. State two applications of nuclear fission and nuclear fusion 

Nuclear fission Supplies energyNuclear fusion Supplies energy Hydrogen bomb

45.  Mention four alloys and their component elements   

AlloysComponent elements
Steel Stainless steel Permallory
Soft solder
Soft solder II
Copper and zinc
Copper and tin
Aluminum, copper, magnesium, and manganese
Iron and carbon
Iron, chromium and nickel Iron and nickel
Lead and tin Lead, tin and antimony

There are other important facts to note in Chemistry and I strongly recommend you keep on checking as will be updating this post regularly

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