1(A Metal substitutes water hydrogen or acid:
Metals react with water as they substitute acid hydrogen and produce salt and hydrogen rises.
2 Na + 2 H2O 2 NaOH + H2 + heat
Q
:
What happens:
if you put 3 pieces of zinc, aluminium and copper in diluted
hydrochloric acid.
1 - The acid reacts with zinc immediately composing salt and hydrogen.
Zn + 2HCl Zn Cl 2 + H 2
2 - Aluminium started to react more strongly than the zinc composing salt and hydrogen. 2Al + 6HCl 2AlCl 3 + 3H 2
3 - The acid does not react with copper??? Bec. Copper is less active than hydrogen of the acid. Cu + HCl No Reaction
2) The substitution of a metal instead of another one into its salt
Some metals replace another metal in its salt solution that follows it in the series of chemical activity.
Magnesium substitutes copper in copper sulfate solution. A reddish brown copper precipitate in the glass and the solution turns to magnesium sulfate
Mg + CuSO4 Mg SO4 + Cu
B) Double substitution reaction:
It is a reaction where double substitution occurs between the ions of two compounds to form two new compounds.
AB + CD → AD + CB
1) Reaction between acid and Alkali. (Neutral)
It is the reaction between an acid and an alkali forming salt and water.
When hydrochloric acid reacts with sodium hydroxide, they produce sodium chloride (salt) and water.
On heating the solution, water evaporates and sodium chloride remains.
NaOH + HCl NaCl + H2O
2) The reaction of acid with salt
Acids react with salt and the resultant depends on the type of acid and salt.
Hydrochloric acid reacts with sodium carbonate forming sodium chloride, water and carbon dioxide which turbids lime water.
Na2CO3+ 2HCl 2NaCl + H2O+CO2
3 ) The Reaction of salt with salt
● Double substitution reactions between salt solutions are accompanied by the formation of a precipitate.
●
When
we add sodium chloride solution to silver nitrate, a white
precipitate
of silver chloride is formed.
NaCl
+ AgNO3
NaNO3
+
AgCl
When hydrogen passes through hot copper oxide, hydrogen takes the oxygen away from copper oxide and water is formed. Copper oxide turns into copper.
H2
+
CuO
Cu
+ H2O
● The reaction of sodium with chlorine includes both oxidation and reduction processes. This reaction gives sodium chloride which is known as table salt.
2 Na + Cl2 2NaCl
2 Na 2Na+ + 2e-
Cl2
+
2e-
2
Cl -
L esson 1 exercises
1- Complete the following sentences:
a Oxidization is a chemical process where the atom ............... an electron or more.
b ............. factor is the substance which gains one electron or more.
c During ....... ......... reactions, the compound breaks up by heat into its simple components.
d .................... is the reaction between an acid and an alkali to form salt and water.
e ................... is the substance which gives oxygen and takes away hydrogen.
2 -Write the scientific term for each of the following statements:
a The breaking up of the molecules of the reactants and the forming of new coherences. ( ---------------------------)
b A chemical process where the atom gains one or more electron.
( ---------------------------)
c It is the substance which loses an electron or more during a chemical reaction.
( ---------------------------)
d A reaction where an element substitutes another one. ( ---------------------------)
3 -Illustrate by equations the following reactions:
a The reaction between hydrochloric acid and sodium hydroxide.
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b Adding silver nitrate solution to sodium chloride solution.
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c The effect of heat on red mercury oxide.
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d The reaction of zinc with diluted hydrochloric acid.
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e The effect of heat on sodium nitrates.
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4- Identify the process of oxidization, reduction, oxidizing factor and reducing factor in each of the following reactions:
2Li + Pb+2 Li+1 + Pb
2Cr+3 + 3Zn 2Cr + 3Zn+2
CH4 + 2 O2 CO2 + 2 H2O