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Chemical Reactions and Equations
Types of Chemical Reactions
Reaction Definition Example
Combination Reaction Two or more reactants combine to form a single product.
CaO + H 2 O → Ca(OH) 2
Decomposition Reaction A single compound decomposes or breaks down to form two or more simpler substances.
2FeSO 4 (s) → Fe 2 O 3 (s) + SO 2 (g) + SO 3 (g)
Displacement Reaction A more reactive element displaces a less reactive element from its aqueous solution.
Zn(s) + CuSO 4 (aq) → ZnSO 4 (aq) + Cu(s)
Double displacement Reaction
Aqueous solutions of two ionic compounds react by exchange of their ions.
Na 2 SO 4 (aq) + BaCl 2 (aq) → BaSO 4 (s) + 2NaCl(aq)
Redox Reaction Reactions involving both loss of electrons (oxidation) and gain of electrons (reduction).
MnO 2 + 4HCl → MnCl 2 + 2H 2 O + Cl 2
Neutralisation Reaction Reaction of an acid and base to form salt and water.
HCl +NaOH → NaCl + H 2 O
Acids, Bases and Salts Chemical Properties of Acids
● Acids react with active metals to give hydrogen gas. Zn + H 2 SO 4 → ZnSO 4 + H 2
● Acids react with metal carbonate and metal hydrogen carbonate to give carbon dioxide.
NaHCO 3 +HCl → NaCl + H 2 O + CO 2 ● Acids react with bases to give salt and water. This reaction is called as neutralization
reaction. NaOH + HCl → NaCl +H 2 O
● Acids react with metals oxides to give salt and water. CuO + H 2 SO 4 → CuSO 4 + H 2 O
Chemical Properties of Bases
● Reaction with Metals Certain reactive metals such as Zinc, Aluminium, and Tin react with alkali solutions on heating and hydrogen gas is evolved.
2NaOH + Zn → Na 2 ZnO 2 + H 2 ● Reaction with acids Bases react with acids to form salt and water.
KOH +HCl → KCl +H 2 O ● Reaction with Non metallic oxides – These oxides are generally acidic in nature. They
react with bases to form salt and water. 2NaOH + CO 2 → Na 2 CO 3 + H 2 O
Some Important Chemical Compounds
Bleaching Powder (CaOCO 2 )
Baking Soda (NaHCO 3 )
Washing Soda (Na 2 CO 3 .10H 2 O)
Plaster of Paris (CaSO 4 . 1/2 H 2 O)
Prepared by passing chlorine gas through dry slaked lime. Ca(OH) 2 + Cl 2 → CaOCl 2 + H 2 O Uses 1. For bleaching cotton and linen in textile industry and wood pulp in paper industry 2. For disinfecting drinking water
Prepared by passing CO 2 gas through brine solution saturated with ammonia. NaCl + H 2 O +CO 2 +NH 3 → NH 4 Cl + NaHCO 3 Uses: 1. It is used in soda – acid fire extinguisher. 2. It acts as mild antiseptic and antacid. 3. It is used as a component of baking powder.
Prepared by heating baking soda. Recrystallisation of sodium carbonate gives washing soda. 2NaHCO 3 → Na 2 CO 3 + H 2 O +CO 2 Na 2 CO 3 + 10H 2 O → Na 2 CO 3 . 10 H 2 O Uses : 1. It is used for removing permanent hardness of water. 2. It is used in glass, soap and paper industries.
Obtained by heating Gypsum upto 373K. CaSO 4 .2H 2 O → CaSO 4 . 1/2 H 2 O + 1 1/2 H 2 O On treatment with water it is again converted into gypsum and sets as a hard mass. CaSO 4 . 1/2 H 2 O+1 1/2 H 2 O → CaSO 4 .2H 2 O Uses: 1. It is used by doctors for setting fractured bones.
3. It can be used as a cleaning agent for domestic purposes.
2. It is used for making statues, models and other decorative materials.
Metals and NonMetals
Physical Properties of Metals and NonMetals
Properties Metals NonMetals
Physical State Metals are solid at room temperature, except mercury and gallium.
Nonmetals generally exist as solids and gases, except bromine
Melting and boiling points
Metals generally have high melting point and boiling point, except gallium and cesium.
Nonmetals have low melting point and boiling point, except diamond and graphite.
Density Generally high Generally low
Malleability and Ductility
Malleable and ductile Neither malleable nor ductile
Electrical and thermal conductivity
Good conductors of heat and electricity Generally poor conductors of heat and electricity, except graphite
Luster Poses shining luster Do not have luster, except iodine
Sonorous sound Give sonorous sound when struck Do not give sonorous sound
Hardness Generally hard except Na, K Solid nonmetals are generally soft, except diamond.
Chemical Properties of Metals and NonMetals
Properties Metals NonMetals
Reaction with Oxygen
Metal + Oxygen → Basic metal oxides (insoluble in water)
NonMetals + Oxygen → Acidic nonmetal oxides (dissolve in water to form acids)
Reaction with Water
Metal + Water → Metal oxides/Metal hydroxides + H 2
Do not react with water Reason: Nonmetals cannot give electrons to hydrogen in water so that it can be released as H2 gas.
Reaction with dilute acids
Metal + Acid → Metal salt + Hydrogen Do not react with dilute acids Reason: Nonmetals cannot lose electrons and give it to Hydrogen ions of acids so that the gas is released.
Reaction with Salt solutions
More reactive metal will displace a less reactive metal from its salt solution.
More reactive nonmetal will displace a less reactive nonmetal from its salt solution.
Reaction with Chlorine
Metal + Chlorine → Metal chloride (ionic bond forms)
NonMetal + Chlorine → Non Metal chloride (covalent bond forms)
Reaction with Hydrogen
Metal + Hydrogen → Metal hydride NonMetal + Hydrogen → Hydride
Carbon and Its Compounds Versatile Nature of Carbon Three important properties of carbon atoms that enable them to form such large number of compounds are:
● Catenation: Property of carbon atom to form bond with other atoms of carbon is known as catenation.
● Tetravalency: Having a valency of 4, carbon atom is capable of bonding with atoms of oxygen, hydrogen, nitrogen, sulphur, chlorine and other elements.
● Small size : The smaller size of carbon atom enables nucleus to hold the shared pair of electrons strongly, making carbon compounds very stable.
Important Chemical Reactions of Carbon Compounds
● Addition Reaction: Formation of larger molecules by addition of more radicals is known as addition reaction. For example: ethene is converted into ethane when heated with the catalyst nickel.
CH2=CH2 + H2 + (Nickel catalyst) ⇨ CH3−CH3
Hydrogenation Reaction: Hydrogen is added to unsaturated hydrocarbons in the presence of nickel to yield saturated hydrocarbons. In this reaction, nickel acts as a catalyst.
● Substitution Reaction: Replacement of a functional group or any atom by another atom or functional group is known as substitution reaction. Substitution reactions are single displacement reactions.
CH4 + Cl2 + Sunlight ⇨ CH3Cl + HCl
● Combustion Reaction: Carbon and carbon compounds gives carbon dioxide, vapor, heat and light on burning in air.
CH4 + 2O2 ⇨ CO2 + 2H2O + Heat + Light
CH3C2OH + O2 ⇨ CO2 + H2O + Heat + Light
● Oxidation:
The gain of oxygen and loss of hydrogen is known as oxidation. In oxidation reaction,
carbon compounds are oxidized in the presence of oxygen.
In these reactions, alkaline potassium permanganate and acidified potassium dichromate act as oxidizing agents and convert alcohol to acids i.e., add oxygen to the starting material.
Important Carbon Compounds ➔ Ethanol (CH 3 CH 2 OH)
Physical Properties Chemical Properties Uses
● Soluble in water ● Burning taste ● Boiling point: 351 K ● Melting point: 156 K
● Reaction with sodium: 2Na + 2CH 3 CH 2 OH → 2CH 3 CH 2 O – Na + + H 2
● Reaction to give unsaturated hydrocarbon:
CH 3 CH 2 OH (in presence of hot conc. H 2 SO 4 ) → CH 2 =CH 2 + H 2 O
● In preparations of soaps and cosmetics
● In alcoholic beverages
● As a laboratory reagent
● In medicines and tonics
➔ Ethanoic Acid (CH 3 COOH)
Physical Properties Chemical Properties Uses
● Miscible in water
● Sour taste ● Boiling
point: 391 K ● Melting
point: 290 K
● Esterification reaction:
Esters react in the presence of an acid or a base to give back alcohol and sodium salt of carboxylic acid as: CH 3 COOC 2 H 5 (in presence of NaOH) → C 2 H 5 OH + CH 3 COOH This reaction is used in the preparation of soaps and is known as saponification reaction .
● Reaction with a base: NaOH + CH 3 COOH → CH 3 COONa + H 2 O
● Reaction with carbonates and hydrogen carbonates:
2CH 3 COOH + Na 2 CO 3 → 2CH 3 COONa + H 2 O + CO 2 CH 3 COOH + NaHCO 3 → CH 3 COONa + H 2 O + CO 2
● In manufacture of vinegar
● Used as organic solvent
● In production of cellulose acetate for photographic film
Cleansing Action of Soap and Detergents
● Soap/detergent are dissolved in water
● The soap molecules arrange themselves such that their hydrophobic ends are away from water molecules and ionic ends are towards water molecules. This is known as micelle formation.
● The oily dirt get accumulated at the centre of micelles.
● When rinsed, it gets easily washed out.
Life Processes
Digestion in Humans
Organ Gland Enzyme/Juice Functions
Mouth Salivary glands Salivary Amylase Converts starch into sugar
Stomach Gastric glands Gastric juice (i) Hydrochloric acid (ii) Pepsin (iii) Mucus
(a) Kills harmful bacteria that enters with the food (b) Makes the medium alkaline for the action of Pepsin Digests proteins Protects the inner lining of the stomach from the corrosive action of Hydrochloric acid
Small Intestine 1) Liver 2) Pancreas
(i) Bile juice → (ii) Pancreatic Juice
● Amylase →
(a) Makes the medium acidic for the action of Pancreatic enzymes (b) Breaks down large fat molecules into smaller globules so that enzymes can act upon them Converts Carbohydrates to glucose
● Trypsin →
● Lipase →
Converts Proteins to Amino acids Converts Fats into Fatty acids & Glycerol
Differences Between Aerobic and Anaerobic Respiration
Aerobic Respiration Anaerobic Respiration
It occurs in the presence of O 2. It occurs in absence of O 2.
It involves the exchange of gases between an organism and outside environment.
Exchange of gases is absent.
It occurs in the cytoplasm and mitochondria. It occurs only in cytoplasm.
It always releases CO 2 and H 2 O. End products may vary (ethanol in bacteria, lactic acid in muscle cells).
It yields 38 ATP. It yields 2 ATP.
Double Circulation
● The right auricle contracts and passes the deoxygenated blood to the right ventricle. ● The right ventricle contracts and passes the deoxygenated blood into the two pulmonary
arteries, which pumps it to the lungs where the blood is oxygenated. ● From the lungs, the pulmonary veins transport the oxygenated blood to the left atrium of
the heart. ● The left atrium contracts and the oxygenated blood enters the left ventricle. ● The blood passes to aorta from the left ventricle. ● The aorta gives rise to many arteries that distribute the oxygenated blood to all the
regions of the body.
● Since the blood goes twice through the heart, it is known as double circulation.
How Do Organisms Reproduce?
Differences Between Sexual and Asexual Reproduction
Sexual Reproduction Asexual Reproduction
It involves two parents. It involves a single parent.
Special sex organs are required. It does not require special sex organs.
It involves meiosis and fusion of gametes. It does not involve meiosis and gametic fusion, instead, mitosis occurs.
Zygote formation takes place. No zygote formation takes place.
Offspring exhibit genetic variation from either of the two parents.
Offspring are genetically similar to parents.