grade 10 physical science - wordpress.com...2018/04/02 · grade 10 physical science 1. aluminium...
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GRADE 10
PHYSICAL SCIENCE
1.
Aluminium𝑨𝒍
phosphorus
carbon dioxide
Hydrogen sulfate
Hydrochloric acid
Sulfuric acid
𝑷
𝑪𝑶𝟐
𝑯𝟐𝑺𝑶𝟒
𝑯𝑪𝒍
𝑯𝟐𝑺𝑶𝟒
2.
Gaseous state (g)Liquid state (l)Solid state (s)Aqueous solution (aq)
𝑁2(𝑔) + 2𝑂2(𝑔) → 2𝑁𝑂2(𝑔)
3.
𝑁2(𝑔) + 2𝑂2(𝑔) → 2𝑁𝑂2(𝑔)
4.
𝑁2(𝑔) + 2𝑂2(𝑔) → 2𝑁𝑂2(𝑔)
2(𝑁𝐻4)2𝐶𝑂3
Examples• Write a balanced chemical equation for the following chemical reactions:
•Aluminium reacts with hydrogen chloride solution to form an aluminium chloride solution and hydrogen gas.
•Nitrogen gas reacts with hydrogen gas to form nitrogen hydride gas (ammonia gas)
Homework
EXERCISE 14 PG. 158-159
Energy changes
• Energy changes in chemical reactions are bigger than the energy changes in physical changes.
•During a chemical change, the temperature increases or decreases because the kinetic energy of the
particles change.
REMEMBERWhen bonds are broken – energy is absorbed
When new bonds are formed – energy is released
Calculating energy change
• Amount of potential energy absorbed to break the bonds –amount of energy released when bonds are broken
• If answer is + - endothermic reaction
(the product is colder than the reactants)
• If answer is - - exothermic reaction
(the product is hotter than the reactants)
• The following possible values are given for potential energies that are absorbed and released for a reaction.
• Calculate the energy change and determine whether the reaction is exothermic or endothermic.
Examples
Energy absorbed tobreak bonds(𝑘𝐽.𝑚𝑜𝑙−1)
Energy absorbed to
release bonds(𝑘𝐽.𝑚𝑜𝑙−1)
Energy change
(𝑘𝐽.𝑚𝑜𝑙−1)
Endothermic or exothermic
(𝑘𝐽.𝑚𝑜𝑙−1)
350 420
870 630
Examples•𝐶𝐶𝑙4 𝑔 + 2𝐹2 → 𝐶𝐹4 𝑔 + 2𝐶𝑙2 𝑔 + 752kJ
Exothermic or endothermic ?
Energy is released - hotter
Examples
•𝐶𝑙𝐹3 g + 514kJ → 𝐶𝑙 𝑔 + 3𝐹(𝑔)
Exothermic or endothermic ?
Energy is absorbed - colder
Homework
EXERCISE 15 pg. 160-161