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WorksheetsChemistry Semester 1 Exam Review
Total questions: 50
Worksheet time: 2hrs 54mins
An unknown substance can not be easily separated. Would the explanation that this substance is an element be valid?
No, because the substance could be a compound, which also cannot be separated by physical means.
No, because the substance could be homogeneous mixture.
Yes, because elements cannot be separated by ordinary chemical means.
Yes, because the substance could be homogeneous mixture.
How many significant figures are in the measurement 811.40 grams?
two
three
four
five
What is the measurement 1042 L rounded off to two significant digits?
1.0 x 103 L
1040 L
1050 L
1.1 x 103 L
What is the density of an object having a mass of 8.0 g and a volume of 25 cm3 ?
0.32 g/cm3
2.0 g/cm3
3.1 g/cm3
200 g/cm3
Which state of matter is characterized by having an indefinite shape, but a definite volume?
gas
liquid
solid
none of these
Which of the following is a physical change/
corrosion
explosion
evaporation
rotting of food
Which of the following CANNOT be classified as a substance?
table salt
air
nitrogen
gold
As a consequence of the discovery of the nucleus by Rutherford, which model of the atom is thought to be true?
Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom.
The nucleus is made of protons, electrons, and neutrons.
Electrons are distributed around the nucleus and occupy almost all the volume of the atom.
The nucleus is made of electrons and protons.
What does the number 84 in the name krypton-84 represent?
the atomic number
the mass number
the sum of protons and electrons
twice the number of protons
Air is a mixture not a compound because
it can be heated to a higher temperature.
it can be compressed to a smaller volume.
Its components are chemically combined.
Its composition can vary.
The label on a bottle of mouthwash tell you it contains "the most fresh breath of any mouthwash on the market." What would be the best way for you to start to evaluate this claim?
See if there's a similar brand of mouthwash that claims to have the "second most fresh breath mouthwash on the market."
Research what ingredients actually freshen breath, and see if the mouthwash contains those ingredients.
Compare the color of the mouthwash with the colors of others on the market.
See if it's repeated anywhere else on the packaging.
Which of the following is an intensive property?
mass
volume
density
length
There are 6.022 x 1023 atoms in one mole of nitrogen. Using scientific notation, how many atom are there in 2.06 mole of nitrogen?
1.24 x 1022
1.24 x 1023
1.24 x 1024
1.24 x 1025
The accuracy of a measurement ...
is how close the measurements in a set are to one another.
indicated that the measurements is also precise.
is how close it is to the true value.
does not depend on the instrument used to measure the object.
Which of the following states an important result of Rutherford's gold-foil experiment?
Atoms have mass.
Electrons have a negative charge.
Neutrons are uncharged praticles.
The atom is mostly empty space.
What is the molar mass when you have 4 moles of CO2?
176.04 grams
54.0 grams
128.2 grams
280 grams
Which of these is correct regarding Thomson's cathode-ray observations?
The experiments helped Thomson discover the proton.
The experiment helped Thomson discover the nucleus.
Cathode rays had identical properties regardless of the element used to produce them.
Negative charge deflects positive charge.
What part of Dalton's atomic theory did scientists modify?
Atoms of an element are identical in size, mass, and other properties.
Atoms cannot be subdivided.
Atoms of different elements combine in simple whole-number ratios to form chemical compounds.
All matter is composed of extremely small particles called atoms.
The nuclear symbol for uranium-235 should be written as
U-235
235 92 U
235143 U
U
What is the molar mass when you have 4 moles of CO2?
176.04 grams
54.0 grams
128.2 grams
280 grams
A solid mass of 35 grams is mixed with 75 grams of a solution. A chemical change occurs and a gas is produced. The final mass of the mixture is 100 grams. What is the mass of the gas released?
110 g
10 g
45 g
15 g
In the equation c = λ v, c represents...
the wavelength
the frequency
the speed of light
Planck's constant
How many quantum numbers are used to describe the properties of electrons in atomic orbitals?
1
2
3
4
5
1s2 2s2 2p6 3s2
1s22s22p63s23p6
4s23d104p6
[Xe] 6s2 4f14 5d9
What is an example of basic research?
Searching for fuels other than gasoline to power cars.
Finding ways to slow down the rusting of iron ships.
Creating synthetic elements to study their properties.
Producing heat-resistant plastics for use in household ovens.
Why does the atom have no net electric charge?
Its subatomic particles carry no electric charges.
The positively charged protons cancel out the negatively charged neutrons.
The positively charged neutrons cancel out the negatively charged electrons.
The positively charged protons cancel out the negatively charged electrons.
The study of the composition, structure, and properties of matter; the processes that matter undergoes; and the energy changes that accompany those processes best describes the science of
biology
physics
astronomy
chemistry
Metalloids lie between metals and nonmetals on the periodic table. They tend to be
nonconductors
conductors
semiconductors
unreactive
