Semester 1- Chemistry Final Exam
To determine the formula of a new substance, one of the first steps is to find the ____
Percent composition
Which to particles each have a mass approximately equal to one atomic mass unit?
Proton and Neutron
What is the empirical formula of a compound that is 40% sulfur and 60% oxygen by weight?
SO3
Which element has both metallic and nonmetallic properties?
Silicon
Which of the following does NOT form a diatomic molecule in its elemental form?
Sulfur
What is the temperature of absolute zero measured in °C?
-273°C
A compound differs from a mixture in that a compound always has a
homogenous composition
The chemical name of FeCl2 is
iron (II) chloride
The chemical name of Fe3(PO4)2 is
iron (II) phosphate
When combining with nonmetallic atoms, metallic atoms generally will
lose electrons and form positive ions
The chemical name of Mg3(PO4)2 is
magnesium phosphate
An atom of carbon-12 and an atom of carbon-14 differ in
mass number
Which is most likely to form a cation?
metal
What is the metric system prefix for the quantity 0.000 001?
micro-
An atomic is electrically neutral because the
number of protons equals the number of electrons
The correct name for SiC is
silicon carbide
Which elements belong in the same family or group?
sodium and potassium
NaClO is named
sodium hypochlorite
Chlorine boils at 239 K. What is the boiling point of chlorine expressed in degrees Celsius?
-34°C
What is the density of an object having a mass of 8.0 g and a volume of 25 cm?
0.32g/cm^3
What is the net charge on an ion that has 9 protons, 11 neutrons, and 10 electrons?
1-
What is the measurement 1042 L rounded off to two significant digits?
1.0E3 L
What is the volume of 80.0 g of ether if the density of ether is 0.70 g/mL?
1.1E2
The diameter of a carbon atom is 0.000 000 000 154 m. What is this number expressed in scientific notation?
1.54E-10 m
What is the charge on the cadmium ion in this compound? Cd(MnO4)2
2+
What is the volume of a salt crystal measuring 2.44E-2 m by 1.4E-3 m by 8.4E-3 m?
2.9E-7 m^3
What is the result of adding 2.5E3 and 3.5E-7?
2.9E3
What is the percent composition of chromium in BaCrO?
20.5%
What is the total number of atoms represented in the formula CuSO4 . 5H2O?
21
What is the temperature -34C expressed in kelvins?
239 K
The atomic masses and the natural abundances of the two naturally occurring isotopes of lithium are shown in the table below. Which numerical setup can be used to determine the atomic mass of lithium?
(0.075)(6.02 u) + (0.925)(7.02 u)
A 100.00-gram sample of naturally occurring boron contains 19.78 grams of boron-10 (atomic mass = 10.01 atomic mass units) and 80.22 grams of boron-11 (atomic mass = 11.01 atomic mass units). Which numerical setup can be used to determine the atomic mass of naturally occurring boron?
(0.1978)(10.01) + (0.8022)(11.01)
Element X has two isotopes. If 72.0% of the element has an isotopic mass of 84.9 atomic mass units, and 28.0% of the element has an isotopic mass of 87.0 atomic mass units, the average atomic mass of element X is numerically equal to
(72.0 × 84.9)/100 + (28.0 × 87.0)/100
What is the total charge of the nucleus of a carbon atom?
+6
If the temperature changes by 100 K, by how much does it change in C?
100°C
Express the product of 2.2 mm and 5.00 mm using the correct number of significant digits
11 mm^2
What is the measurement 111.009 mm rounded off to four significant digits?
111.0 mm
Express the sum of 7.68 m and 5.0 m using the correct number of significant digits
12.7 m
What is the total number of electrons in an atom of potassium?
19
What is the total number of carbon atoms in ethanoic (acetic) acid, (also known as vinegar), with a molecular formula CH3COOH?
2
Which expression represents the percent by mass of nitrogen in NH4NO3?
28 g N/80 g NHNO 100%
How many significant figures are in the measurement 40,500 mg?
3
In the measurement 0.503 L, which digit is the estimated digit?
3
Express the product of 4.0 10 m and 8.1 10 m using the correct number of significant digits
3.2E1
What is the boiling point of water in kelvins?
373 K
What is the volume of 45.6 g of silver if the density of silver is 10.5 g/mL?
4.34 mL
An ion with 5 protons, 6 neutrons, and a charge of 3+ has an atomic number of
5
How many significant figures are in the measurement 811.40 grams?
5
The expression of 5008 km in scientific notation is ____
5.008E3 km
If 20.0 grams of Ca combines completely with 16.0 grams of S to form a compound, what is the percent composition of Ca in the compound?
55.6%
What is the mass number of an atom which contains 28 protons, 28 electrons, and 34 neutrons?
62
What is the percent by mass of carbon in acetone, CHO?
62.1%
Which of the following measurements is expressed to three significant figures?
7.30E-7
If 60.2 grams of Hg combines completely with 24.0 grams of Br to form a compound, what is the percent composition of Hg in the compound?
71.5%
The total number of atoms in one molecule of the compound K3PO4 is
8
What is the result of multiplying 2.5E10 by 3.5E-7?
8.75E3
What is the percent composition of carbon, in heptane, CH?
84%
The nucleus of element O has
9
Which is an example of a chemical change?
A nail rusting
What was concluded about the structure of the atoms as a result of the golf foil experiment?
A positively charged nucleus is surrounded by mostly empty space
Which of the following substances can be decomposed (broken down) by chemical means?
Ammonia, NH3
What determines the order of placement of the elements on the modern Periodic Table?
Atomic number
The ratio of carbon atoms to hydrogen atoms to oxygen atoms in a molecule of dicyclohexyl maleate is 4 to 6 to 1. What is its molecular formula if its molar mass is 280 g?
C16H24O4
Which of the following is NOT an empirical formula?
C2N2H8
Which of the following compounds have the same empirical formula?
C7H14 and C10H20
What is the formula for carbon tetrachloride?
CCl4
Which of the following sets of empirical formula, molar mass, and molecular formula is correct?
CH4N, 90 g, C3H12N3
What is the formula for carbon dioxide?
CO2
Plaster of Paris, drywall, and the mineral gypsum are all calcium sulfate. What is the formula of calcium sulfate?
CaSO4
The average atomic mass recorded on the periodic table for cobalt is 58.933 u. This indicates that the most abundant isotope of cobalt is
Cobalt-59
What is the formula for chromium (III) phosphate?
CrPO4
In naming acids, what is the first question you should ask yourself?
Does the anion have oxygen?
Which element is most chemically similar to chlorine?
Flourine
Which of these elements has physical and chemical properties most similar to silicon (Si)?
Germanium (Ge)
Which element below is in the same column as the alkali metals, but is not a metal?
H
Which of the following compounds has the highest oxygen content, by weight?
H2O
The formula for potassium permanganate is
KMnO4
Which temperature scale has no negative temperatures?
Kelvin
When alpha particles are scattered by thin metal foils, which observation indicates a very high percentage of space in atoms?
Most pass through with little or no deflection
The formula for dinitrogen pentaoxide is
N2O5
Ammonium nitrate is used as a fertilizer, to make cold packs, and as an explosive. What is the formula of ammonium nitrate?
NH4NO3
What is the formula of nitrogen triiodide?
NI3
It is important to be able to recognize the ions in an ionic compound. The name of the ionic compound gives you this information. What are the ions in sodium chloride?
Na+, Cl-
he correct formula for sodium chloride (table salt) is
NaCl
Which gas is monatomic at standard room conditions?
Neon
Which symbols represent atoms that are isotopes?
O-16 and O-18
Which atom contains exactly 15 protons?
P-32
Which of the following is NOT true about empirical and molecular formulas?
The empirical formula of a compound can be triple its molecular formula.
What information is needed to calculate the percent composition of a compound?
The formula of the compound and the atomic mass of its elements
Matter that is composed of two or more different elements chemically combined in a fixed proportion is classified as
a compound
Petroleum is classified chemically as
a mixture
The closeness of a measurement to its true value is a measure of its ____
accuracy
The chemical name of Al(NO3)3 is
aluminum nitrate
A proton has a charge that is opposite the charge of
an electron
A sample composed only of atoms having the same atomic number is classified as
an element
The chemical name of Cd(MnO4)2
cadmium permanganate
P2O5 is named
diphosphorus pentoxide
The lowest whole-number ratio of the elements in a compound is called the ____
empirical formula
All of the following involve chemical changes, except
the dissolving of a sugar cube in a cup of coffee
The atomic mass of titanium is 47.88 atomic mass units. This atomic mass represents the
weighted average mass of all the naturally occurring isotopes of Ti