General Chemistry I - chapter 3 PDF

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general chemistry 1
formulas, molecules, reactions
hemmes...

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General Chemistry I – Ch. 3 •

Chemical reactants o Reactants: starting substance o Products: substances produced o Balanced chemical equation must have equal numbers of atoms of each elements on each side of the arrow o The number of atoms is obtained by multiplying each subscript a chemical formula by the coefficients for the formula o Balancing equations §

Should contain possible whole number coefficients

§

Never change subscripts when balancing an equation

o Indication the states of reactants and products § •

Use (g), (s), (l), (aq)

Simple patterns of chemical reactivity o Combination reactions: two or more substances react to form one production §

𝐴+𝐵 →𝐶

§

𝐶(') + 𝑂*(+) → 𝐶𝑂*(+)

§

Combination reaction between a metal and a nonmetal produces an ionic solid

o Decomposition reaction: one substance undergoes a reaction produce two or more other substances §

𝐶 →𝐴+𝐵

§

𝐶𝑎𝐶𝑂-(') → 𝐶𝑎𝑂(') + 𝐶𝑂*(+)

o Combustion reaction: rapid reactions that produce a flame

§ •

𝐶- 𝐻/(+) + 5𝑂*(+) → 3𝐶𝑂*(+) + 4𝐻* 𝑂(+)

Formula weights o Formula weight (FW): sum of atomic weights (HW) of the atoms in the chemical formula of the substance o Molecular weight (MW): chemical formula of a molecule o Percentage composition from chemical formulas §

Percentage by mass contributed by ach element in the substance

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Elemental composition: percentage composition of element

§ •

% mass comp. of element =

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