Chemical reaction: It is a process that involves breaking the existing bonds in the reactant molecules and forms new bonds in the products. Importance of chemical reactions: 1. Burning of car fuel in the car engine. 2. Plants make their food through photosynthesis process. 3. Medicine, fertilizers, artificial fibers are examples of outcomes of some chemical reactions. 1
1. Thermal decomposition reactions. 2. Substitution reactions. 3. Oxidation reduction reactions. 2
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2 HgO 2Hg + O 2 4
Cu(OH) 2 CuO + H 2 O blue black 5
CuCO 3 CuO +CO 2 Green black 6
CuSO 4 CuO + SO 3 blue black 7
2NaNO 3 2 NaNO 2 + O 2 8
Air bags: They are considered one of the most important safety means in cars at emergencies. 9
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They are the reactions which depend on the activity of the metals, where the element which is more active substitutes (replaces) the less active one in its compounds. The activity of metals can be determined by using the “chemical activity series” 11
It is the arrangement of the metals in an descending order according to their chemical activity. 12
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1.Simple substitution reactions 2. Double substitution reactions 14
+ + Types of simple substitution reactions A. Metal substitutes Hydrogen of acid or water. B. Metal substitutes another metal in its salt solution. 15
2Na +2 H 2 O 2NaOH + H 2 16
Zn + 2HCl ZnCl 2 +H 2 17
2Al + 6HCl 2AlCl 3 +3H 2 18
Mg + CuSO 4 MgSO 4 +Cu 19
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1. Reaction between acid and alkali ( Neutralization reaction) 2. Reaction between acid and salt. 3. Reaction between two salt solution. 22
Acid + Alkali Salt + Water HCl + NaOH NaCl + H 2 O 23
NaCO 3 + 2HCl 2NaCl + H 2 O+CO 2 3. Reaction between two salt solution. NaCl +AgNO 3 NaNO 3 +AgCL 24
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