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13 Cards in this Set
- Front
- Back
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Define an Atom. |
An atom is the smallest particle of an element which can take part in chemical reactions. |
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Define Atomicity. |
This is the number of atoms in each molecule of an element. |
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Define a Molecule and give examples. |
A molecule is the smallest particle of a substance that can normally exist alone and still retain the chemical properties of that substance. e.g Hydrogen Molecule (H2), Fluorine Molecule (F2). |
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1. (a) Arrange the three states of matter in order of decreasing:(i) kinetic energy;(ii) force of cohesion. (WAEC) |
(I) Solid<Liquid<Gas (II) Solid>Liquid>Gas or Gas<Liquid<Solid |
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Define an ion |
An ion is any atom or group of atoms which possesses an electric charge. |
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State the types of ion |
Cations and anions |
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State dalton's atomic theory |
1.All elements are made up of small, indivisible particles called atoms. 2.Atoms can neither be created nor destroyed. 3.Atoms of the same elements are alike in every aspect, and differ from atoms of all other elements. 4.When atoms combine with other atoms,they do so in simple ratio. 5.All chemical changes results from the combination or the separation of atoms |
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Why does the mass of an atom or a relative atomic mass carry no units ? |
It is only a ratio |
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The mass of an atom can be measured with what ? |
The mass spectrometer |
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Define atomic mass |
The relative atomic mass, A of an element is the number of time the average mass of the atom of that element is heavier than one-twelfth the mass of one atom of carbon-12 |
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Define relative molecular mass |
The relative molecular mass, M of an element or a compound is the number of times the average mass of one molecule of it is heavier than one-twelfth the mass of one atom of carbon-12 |
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Example; Calulate the relative molecular mass of limestone, CaCO3. (Ca = 40,C = 12,O = 16) |
One molecule of CaCO3 has 1 Ca, 1 C and 3 O atoms. :- relative molecular mass of CaCO3 = 1×A, of Ca + 1 ×A, of C +3×A, of O = ( 1×40 + 1 × 12 + 3 × 16) = 100 |
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Define mole |
One mole of a substances is the amount containing as many elementary entities as the number of atoms in exactly 12 grams of carbon -12( The short form for mole mol.) |
