|줌달의 일반화학 8판 솔루션 사이플러스에 대한 자료입니다.
ATOMS, MOLECULES, AND IONS
TYPES OF CHEMICAL REACTIONS AND SOLUTION
ATOMIC STRUCTURE AND PERIODICITY
BONDING: GENERAL CONCEPTS
COVALENT BONDING: ORBITALS
LIQUIDS AND SOLIDS
PROPERTIES OF SOLUTIONS
ACIDS AND BASES
SOLUBILITY AND COMPLEX ION EQUILIBRIA
SPONTANEITY, ENTROPY, AND FREE ENERGY
THE NUCLEUS: A CHEMIST'S VIEW
19. A law summarizes what happens, e.g., law of conservation of mass in a chemical reaction or
the ideal gas law, PV = nRT. A theory (model) is an attempt to explain why something
happens. Dalton’s atomic theory explains why mass is conserved in a chemical reaction. The
kinetic molecular theory explains why pressure and volume are inversely related at constant
temperature and moles of gas present, as well as explaining the other mathematical
relationships summarized in PV = nRT.
20. A dynamic process is one that is active as opposed to static. In terms of the scientific
method, scientists are always performing experiments to prove or disprove a hypothesis or a
law or a theory. Scientists do not stop asking questions just because a given theory seems to
account satisfactorily for some aspect of natural behavior. The key to the scientific method is
to continually ask questions and perform experiments. Science is an active process, not a
21. The fundamental steps are
(1) making observations;
(2) formulating hypotheses;
(3) performing experiments to test the hypotheses.
The key to the scientific method is performing experiments to test hypotheses. If after the test
of time the hypotheses seem to account satisfactorily for some aspect of natural behavior,
then the set of tested hypotheses turns into a theory (model). However, scientists continue to
perform experiments to refine or replace existing theories.
22. A random error has equal probability of being too high or too low. This type of error occurs
when estimating the value of the last digit of a measurement. A systematic error is one that
always occurs in the same direction, either too high or too low. For example, this type of
error would occur if the balance you were using weighed all objects 0.20 g too high, that is, if
the balance wasn’t calibrated correctly. A random error is an indeterminate error, whereas a
systematic error is a determinate error.
23. A qualitative observation expresses what makes something what it is; it does not involve a
number; e.g., the air we breathe is a mixture of gases, ice is less dense than water, rotten milk
The SI units are mass in kilograms, length in meters, and volume in the derived units of m3.
The assumed uncertainty in a number is "1 in the last significant figure of the number. The
precision of an instrument is related to the number of significant figures associated with an
experimental reading on that instrument. Different instruments for measuring mass, length, or
volume have varying degrees of precision. Some instruments only give a few significant
figures for a measurement, whereas others will give more significant figures.
2 CHAPTER 1 CHEMICAL FOUNDATIONS
24. Precision: reproducibility; accuracy: the agreement of a measurement with the true value.
a. Imprecise and inaccurate data: 12.32 cm, 9.63 cm, 11.98 cm, 13.34 cm
b. Precise but inaccurate data: 8.76 cm, 8.79 cm, 8.72 cm, 8.75 cm
c. Precise and accurate data: 10.60 cm, 10.65 cm, 10.63 cm, 10.64 cm
Data can be imprecise if the measuring device is imprecise as well as if the user of the
measuring device has poor skills. Data can be inaccurate due to a systematic error in the
measuring device or with the user. For example, a balance may read all masses as weighing
0.2500 g too high or the user of a graduated cylinder may read all measurements 0.05 mL too
A set of measurements that are imprecise implies that all the numbers are not close to each
other. If the numbers aren’t reproducible, then all the numbers can’t be very close to the true
value. Some say that if the average of imprecise data gives the true value, then the data are
accurate; a better description is that the data takers are extremely lucky.
25. Significant figures are the digits we associate with a number. They contain all of the certain
digits and the first uncertain digit (the first estimated digit). What follows is one thousand
indicated to varying numbers of significant figures: 1000 or 1 × 103 (1 S.F.); 1.0 × 103 (2
S.F.); 1.00 × 103 (3 S.F.); 1000. or 1.000 × 103 (4 S.F.).
To perform the calculation, the addition/subtraction significant figure rule is applied to 1.5 !
1.0. The result of this is the one-significant-figure answer of 0.5. Next, the multiplication/
division rule is applied to 0.5/0.50. A one-significant-figure number divided by a
two-significant-figure number yields an answer with one significant figure (answer = 1).
26. The volume per mass is the reciprocal of the density (1/density). The volume per mass
conversion factor has units of cm3/g and is useful when converting from the mass of an object
to its volume in cm3.
27. Straight line equation: y = mx + b, where m is the slope of the line and b is the y-intercept. For
the TF vs. TC plot:
= (9/5)TC + 32
y = m x + b
The slope of the plot is 1.8 (= 9/5) and the y-intercept is 32EF.
|줌달 일반화학 8판 솔루션입니다. ch1~ch19 완판
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