Solutions manual
to accompany
Chemistry 3rd edition
by Blackman, Bottle, Schmid,
Mocerino & Wille
Prepared by
Allan Blackman
© John Wiley & Sons Australia, Ltd 2016
Chapter 1: The atom
Practice exercises
1.1 The first sample has a ratio of:
The law of definite proportions tells us that the second sample must have the same ratio of Ti to O:
Rearranging the equation to solve for x gives:
1.2 (a) number of protons = 71; number of neutrons = (177 – 71) = 106
(b) number of protons = 54; number of neutrons = (133 – 54) = 79
(c) number of protons = 77; number of neutrons = (192 – 77) = 115
1.3 Average atomic mass of Ne:
= (0.9048 × 19.9924 u) + (0.0027 × 20.9938 u) + (0.0925 × 21.9914 u)
= 20.18 u
Review questions
1.1 An atom is a chemical species comprising a central positively charged nucleus surrounded by one or more negatively charged electrons.
A covalent bond is a chemical bond which involves the sharing of electrons between neighbouring atoms.
An ion is a charged chemical species; the charge may be either positive or negative.
A cation is a positively charged chemical species.
An anion is a negatively charged chemical species.
An element is a chemical species comprised of only a single type of atom.
A compound is a chemical species comprised of two or more elements in a definite and unchanging proportion.
A reactant is a chemical species which is transformed in a chemical reaction.
A chemical reaction is a process whereby one or more chemical species is/are transformed into different chemical species. This generally involves the making and/or breaking of chemical bonds.
A product is the species formed in a chemical reaction.
1.2 The first law of chemical combination is the law of conservation of mass: no detectable gain or loss of mass occurs in chemical reactions.
The second law is the law of definite proportions: in a given chemical compound, the elements are always combined in the same proportions by mass.
The third law is the law of multiple proportions: whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.
1.3 The law of conservation of mass says that mass is conserved in chemical reactions. This being the case, then there must be the same mass on either side of the arrow in a chemical equation, and hence the same number of each type of atom on either side of the arrow.
1.4 The law of definite proportions. Chemical elements always combine in a definite fixed proportion by mass to form chemical compounds.
1.5 The ratio of small whole numbers, mentioned in the law of multiple proportions, is consistent with the existence of discrete entities that combine with each other in integer multiples. These discrete entities are atoms.
1.6
. This isotope has a mass of 12 u (exactly) by definition.1.7 They passed through undeflected because most of the atom is empty space and they did not encounter any particles that could deflect them. The force that did lead to some deflections was electrostatic; both the atomic nucleus and alpha particles are positively charged, and will repel each other.