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General Chemistry exam 1 review 2024/2025 Questions With Completed & Verified Solution.
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General Chemistry exam 1 review 2024/2025 Questions With Completed & Verified Solution.
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General Chemistry exam 1 reviewChemical properties - ANS Chemical properties describe the characteristic ability of a
substance to react to form new substances.
Physical properties - ANS Physical properties are characteristics that can be measured without
changing the composition of the sample under study
Elements - ANS contain only one type of atom
Mixtures - ANS contain more than one type of molecule
Compounds - ANS Contain more than one type of atom, but only one type of molecule
Heterogeneous Mixtures - ANS mixtures that are not uniform and so different patches are often
visible.
Homogeneous Mixtures - ANS mixtures that have uniform composition throughout
Density - ANS Density is an intensive physical property that relates the mass of an object to its
volume.
Density=mass/volume (eg. g/mL)
Density of Water - ANS 1.0 g/mL
Intensive property - ANS An intensive property is independent of the amount of the sample.
Intensive properties are most useful for identifying unknown substances.
Extensive property - ANS An extensive property varies with the amount of the sample.
Sig Fig rules - ANS 1.Nonzero integers are always significant.
2.Zeros between two nonzero integers are always significant. 3.Zeros to the left of the first
nonzero digit are not significant. 4.Zeros before a decimal point and after a nonzero number are
significant.
5.Zeros after a nonzero digit are known to be significant if, and only if, the number contains a
decimal point. If the number does not contain a decimal point, the zeros are either not significant
or are ambiguous.
Sig Fig rules in calculations - ANS 1.For multiplication or division, the answer will have the
same number of significant figures as that of the number that has the fewest significant figures.
2.For addition or subtraction, the answer will have the same number of decimal places as that of
the number with the fewest decimal places.
, Accuracy - ANS Accuracy describes the correlation between the measured value and the
accepted value. The accuracy of a measurement, or set of measurements, can be expressed in
terms of error:
error=(average measurement)−(accepted value)
The larger the error is, the less accurate is the measurement.
Precision - ANS Precision describes the reproducibility of a measurement. To evaluate the
precision of a set of measurements, start by finding the deviation of each individual
measurement in the set from the average of all the measurements in the set:
deviation=∣(individual measurement )−(average measurement )∣
The average of all the deviations in the set is called the average deviation. The larger the
average deviation is, the less precise is the data set.
Chemical reaction/chemical change - ANS A chemical reaction (also known as a chemical
change) produces substances that are chemically different from the starting materials. An
example of a chemical reaction is the formation of water from hydrogen and oxygen gas.
Physical Change - ANS In a physical change, a substance changes its physical appearance but
not its chemical identity. An example of physical change is the formation of liquid water from
solid water melting)
Measuring sig figs - ANS When we report a measurement in science, we are careful to report
only digits known with certainty, plus a final digit that is recognized to be uncertain.
Dalton's Atomic Theory - ANS 1.Each element is composed of extremely small particles called
atoms.
2.All atoms of a given element are identical to one another in mass and other properties, but the
atoms of one element are different from the atoms of other elements.
3.Atoms of an element are not changed into atoms of a different element by chemical reactions;
atoms are neither created nor destroyed in chemical reactions.
4.Compounds are formed when atoms of more than one element combine; a given compound
always has the same relative number and kind of atoms.
Electrons: mass, charge - ANS 9.109*10^-28, -1
Protons: mass, charge - ANS 1.673*10^-24, +1
Neutrons: mass, charge - ANS 1.673*10^-24, 0
Z number - ANS The atomic number Z is the number of protons in the nucleus of an atom of an
element. Each element has a unique number of protons
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