A
Z
Chemistry Learning Objectives
Chapter 1 Matter—Its Properties and Measurement
1. Determine the number of significant figures in a number and express the
result of a calculation with the appropriate number of significant figures.
•
All nonzero digits are significant
•
(1) zeros before the decimal point, or (2) zeros following the
decimal point and preceding the first nonzero digit are
not
significant
•
terminal zeros that precede the decimal in numbers greater than
one are ambiguous (ie. 7500m – 2 sig figs)
Ex.
0 . 0 0
4 0 0 4 5 0 0
(7 sig figs 
Bold = not significant)
•
When multiplying or dividing…the final answer may only contain as
many sig figs as the least precisely known quantity in the
calculation
(ie. 14.79 x 12.11 x 5.05 = 904)
•
When adding or subtracting…the final answer must have the same
number of digits after the decimal point as the quantity carrying the
smallest number of such digits (ie. 15.02+9986.0+3.518=10,004.5)
2. Express numbers in scientific notation.
•
Ex. Express 14,775.098 in 3 sig figs = 1.48x10
4
3. Write a conversion factor from a relationship between two quantities, and
use conversion factors to solve problems; e.g. density = mass/volume.
•
Kelvin from Celsius
T(K)=t(C) +273.15
•
Fahrenheit from Celsius
9/5 x t(C) + 32
•
Celsius from Fahrenheit
5/9 x [t(F) – 32]
•
Density(d)=Mass(m)/Volume(V) – Mass & Volume are Extensive
Properties because they depend on the quantity of matter. Density
is an Intensive Property because it is independent of the amount of
matter involved.
•
Conversion Pathway: relating units to map out solutions
Ex. Find the mass of a cube of osmium that is 1.25 in. on edge, and a
density of 22.59g/cm
3
.
in. osmium
cm osmium
cm
3
osmium
g osmium
? g Osmium = [1.25 in. x 2.54 cm]
3
x 22.59 g/cm
3
= 723 g
4. Solve algebraic equations that arise in the course of working chemistry
problems.
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View Full DocumentChapter 2 Atoms and the Atomic Theory
1. What are the numbers of protons, neutrons, and electrons present in given
atoms, (using the symbolism
E
) and how can isotopes and ions of an
element be identified?
•
A =
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 Spring '08
 H
 Chemistry, Atom, atoms, Sig Figs

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