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Practice Make Perfect 3!

Practice Make Perfect 2!

1.5 Gas Test Video

Dear students, this video help you to understand the gast test.

1.5 Gas Test

Gas	Example of Preparation	Test
Oxygen (O2)	Decomposition of hydrogen peroxide H2O2 -----> H2O + ½O2(g) Thermal decomposition of some metallic oxides 2PbO -----> 2Pb + O2(g)	Ignites a glowing splint since oxygen supports combustion
Hydrogen (H2)	acid + metal -----> salt + hydrogen gas 2HCl + Zn -----> ZnCl2 + H2(g) active metal + water -----> hydroxide + hydrogen gas Ca(s)+ 2H2O--->Ca(OH)2+ H2(g)	"Pop Test" : a lit taper will produce an audible "pop" when placed in hydrogen gas
Carbon dioxide (CO2)	acid + carbonate -----> salt + water + carbon dioxide 2HCl+CaCO3-->CaCl2+H2O+CO2(g) Thermal decomposition of some carbonates CuCO3 -----> CuO + CO2(g)	When CO2(g) is bubbled through colourless limewater (Ca(OH)2(aq))the limewater turns milky due to the formation of a calcium carbonate (CaCO3(s)) precipitate. When CO2(g) is bubbled through Ba(OH)2(aq) a white precipitate of BaCO3 forms.
Nitrogen dioxide (NO2)	Thermal decomposition of some nitrates 2Ni(NO3)2--->2NiO + O2+ 4NO2(g) 2Pb(NO3)2--->2PbO + O2+4NO2(g) Less active metals + nitric acid -----> nitrate + water + nitrogen dioxide Cu + 4HNO3 ---> Cu(NO3)2 + 2H2O + 2NO2(g)	Nitrogen dioxide is a red-brown gas which is soluble in water and has a pungent odour.
Sulfur dioxide (SO2)	Combustion of sulfur S(s) + O2 -----> SO2(g) Sulfites + acid -----> water + sulfur dioxide SO32- + 2H+ -----> H2 + SO2(g) Hot concentrated sulfuric acid + copper 3H2SO4 + Cu(s) --->Cu2++2HSO4-+2H2O +SO2(g)	SO2(g) is bubbled through hydrogen peroxide solution (H2O2) to produce sulfuric acid (H2SO4). The addition of barium chloride solution (BaCl2(aq)) to this solution results in a precipitate of barium sulfate (BaSO4(s)). SO2(g) passed through a concentrated, acidified solution of potassium dichromate (K2Cr2O7) causes the dichromate solution to change colour from orange to green due to the formation of chromium (III) ions (Cr3+).
Hydrogen sulfide (H2S)	sulfide + acid -----> salt + hydrogen sulfide FeS(s) + 2HCl ---> FeCl2 + H2S(g)	H2S is often referred to as "rotten egg gas" as it smells just like rotten eggs! H2S(g) is passed through a solution of zinc chloride (ZnCl2) and a white precipitate of zinc sulfide forms (ZnS(s)). Pass H2S(g) over a damp filter paper impregnated with lead (II) nitrate (Pb(NO3)2), the paper turns black as lead (II) sulfide (PbS(s)) forms.
Chlorine (Cl2)	MnO2(s) + 2Cl- + 4H+ --->Mn2+ + 2H2O + Cl2(g) Electrolysis of molten sodium chloride (NaCl) 2NaCl -----> 2Na(Hg) + Cl2(g) (Na(Hg) is a mercury amalgam of sodium metal since sodium is slightly soluble in mercury but doesn't react with mercury as it does with other solvents like water.)	Cl2(g) is a pale yellow-green gas which bleaches coloured materials and has a characteristic choking odour.

Announcement 1!

1.4 Qualitative Analysis

Next we are going to learn about qualitative analysis. What is qualitative analysis? Qualitative analysis is a Techniques for identify species in chemistry. It involves several techniques such as

• Physical properties (colour and solubility)
• Gas test
• Action of heat
  
• Cation Test
• Anion Test
• Confirmatory Test

8.2 (a) meaning of qualitative analysis

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Quiz 1

Lets Try to answer this questions students!

• Question 1

• Question 2

• Question 3

• Question 4
  

Laughter The Best Medicine 1!

Chemistry Joke!

Practice Make Perfect 1!

Hye beloved students!u have learned about soluble and insoluble salt in previous post isn't it?alright!so lets make a simple excercise to test whether u understand the previous lesson or not!enjoy students!

1.3 Preparation of Insoluble Salt

Insoluble Salt

Precipitation Process aka Double Decomposition Method
Here is the note for u beloved students to make u more understand in this chapter.
Enjoy!!

8.1 (c) insoluble salts

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1.2 Preparation of Soluble Salt

Salt Preparation

1. Soluble Salt
1.1 Acid + Alkali --> SALT + Water
1.2 Acid + Metal --> SALT + Hydrogen
1.3 Acid + Metal Oxide --> SALT + Water
1.4 Acid + Metal Catbonate --> SALT + Water + Carbon dioxide

Below is the complete notes about preparation of soluble salt.Hope it will help u students!

8.1 (b) Preparation of Soluble salts

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1.1 What is Salt ?

Salt :
Salt is an ionic compound formed when hydrogen ion in acid is replaced bt metal ion or ammonium ion.

Example :

HCl + NaOH --> NaCl + H2O

sodium ion replace hydrogen ion to formed sodium chloride salt.

Here some note about 2 class of salt, Soluble and Insoluble salt.

What is Salt?

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