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(Choose and mark the correct answer)
دوري اول 1
A1- Which of the following is a SI base unit?
a- kilometer b- gram c- second d- Celsius
A2- Express 7500 nm as micrometer
a- 7.50 µm b- 75.0 µm c- 7.5 ´ 106 µm d- 7.5 ´ 1012 µm
A3- Which of these quantities represents the largest mass?
a- 2.0 ´ 102 mg b- 0.0010 kg c- 1.0 ´ 105 mg d- 2.0 ´ 102 cg
A4- How many milliliters is 0.005 L?
a- 0.5 mL b- 5 mL c- 50 mL d- 500 mL
A5- The scientist who determined the magnitude of the electric charge of the electron was
a- Robert Millikan b- J. J. Thomson
c- Ernest Rutherford d- James Chadwick
A6- A sodium ion, Na+, has (p = protons and e = electrons)
a- 23 p and 11 e b- 23 p and 10 e c- 11 p and 12 e d- 11 p and 10 e
A7- The appropriate symbol for the isotope with Z = 51 and A = 122 is
a- b- c- d-
A8- Use the following table and choose which of the species are neutral?
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atom or ion of element
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A
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B
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C
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D
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E
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F
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Number of electrons (e-)
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6
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10
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18
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10
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28
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7
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Number of protons (p)
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6
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8
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17
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11
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30
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7
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Number of neutrons (n)
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6
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8
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18
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11
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36
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6
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a- C and E b- B and C c- D and E d- A and F
A9- Atoms with the same number of protons and with different number of neutrons are called
a- ions. b- neutral atoms c- isotopes. d- different atoms.
A10- The elements in a column of the periodic table are known as
a- metal. b- a period. c- a group. d- nonmetal
A11- Which of these pairs of elements would be most likely to form an ionic compound?
a- P and Br b- Cu and K c- C and O d- O and Zn
A12- Which one of these species is an ion?
a- B3+ b- NaCl c- He d- 14C
A13- Which pair of the following compounds has the same empirical formula?
a- C2H6O3 and CH2O b- NO2 and N2O4 c- C6H6and CH4 d- NO2 and NO
A14- The correct name for N2O3 is
a- nitrogen trioxide b- dinitrogen trioxide
c- nitrogen oxide d- dinitrogen oxide
A15- The correct name for Al2O3 is
a- aluminum trioxide b- dialuminum trioxide
c- aluminum oxide d- dialuminum oxide
A16- The correct names for H2S and H2O are
a- dihydrogen sulfide and dihydrogen oxide
b- hydrogen sulfide and water
c- hydrogen sulfide and hydrogen oxide
d- dihydrogen sulfide and water
A17- The Stock system name for CrSO3 is
a- chromium sulfide b- chromium(II) sulfate
c- chromium(II) sulfite d- chromium(III) sulfite
A18- Which of these elements is chemically similar to copper?
a- sulfur b- calcium c- bromine d- silver
A19- The bromine atom has two staple isotopes (Br-79 and Br-81). The atomic masses of (50.690 %) and (49.310 %) are 78.919 amu and 80.916 amu, respectively. Calculate the average atomic mass of bromine. The percentages in parentheses denote the relative abundances.
a- 79.903 amu b- 79.931 amu c- 79.917 amu d-159.834 amu
A20- Calculate the percent composition by mass of C in picric acid (C6H3N3O7).
a- 1.3 % b- 18.3 % c- 31.4 % d- 48.9 %
A21- How many molecules of ethane (C2H6) are present in 0.30 g of C2H6?
a- 1.20 x 1022 b- 1.00 x 1022 c- 8.03 x 1021 d- 6.02 x 1021
A22- Calculate the number of O atoms in 2.00 g of glucose (C6H12O6)
a- 2.01 x 1022 b- 4.01 x 1022 c- 6.02 x 1022 d- 8.03 x 1022
A23- Which of the following samples contains the greatest number of lead atoms?
a- 100 g of Pb b- 0.5 mole of PbO
c- 2.0 mole of PbCO3 d- 0.1 mole Pb3(PO4)2
A24- The empirical formula of an organic compound with 85.7% C and 14.3% H is
a- CH b- CH2 c- C2H d- CH4
A25- An empirical formula of an organic compound is C3H4O2, if the molecular weight of the compound is (360 g/mol), the molecular formula of the compound will be:
a- C6H8O4 b- C12H16O8 c- C9H12O6 d- C15H20O10
A26- The following reaction describes combustion of an alkane, the correct balance will be with
a C5H12 + b O2 → c CO2 + d H2O
a- a = 5, b = 2, c = 2, d = 2 b- a = 12, b = 2, c = 2, d = 2
c- a = 1, b = 8, c = 5, d = 6 d- a = 1, b = 4, c = 5, d = 6
A27- Sodium metal and water react to form sodium hydroxide and hydrogen gas. The mass of Na that will react with excess water to produce 16.0 g NaOH is
2Na(s) + 2H2O(l) → H2(g) + 2NaOH(aq)
a- 5.75 g b- 6.90 g c-8.05 g d- 9.20 g
A28- For the reaction:
2 PbS (s) + 3 O2 (g) → 2 PbO (s) + 2 SO2 (g)
If 5.0 mol of PbS reacts with excess oxygen, how many moles of SO2 will produced?
a- 2.5 b- 5.0 c- 7.5 d- 10.0
A29- How many grams of SF4 (g) can theoretically be prepared from 6.00 g of SCl2 (g) and 3.50 g of NaF(s)? The equation of reaction is:
3 SCl2 (g) + 4 NaF (s) → SF4 (g) + S2Cl2 (l) + 4 NaCl (s)
a- 21.0 g SF4 b- 210 g SF4 c- 2.10 g SF4 d- 0.210 g SF4
A30- Hydrogen fluoride is used in the manufacture of Freon (which destroy ozone in the stratosphere) and in the production of aluminum metal. In one process 6.000 kg of CaF2 are treated with an excess of H2SO4 and yield 2.860 kg of HF. Calculate the percent yield of HF. It is prepared by the reaction: CaF2 + H2SO4 à CaSO4 + 2HF
a- 85.0 % b- 88.0 % c- 93.0 % d- 95.0 %
دوري اول 2
(Choose
and mark the correct answer)
A1- The
diameter of an atom is approximately 1 ´
10-8 cm. What is this diameter when expressed in nanometers?
a- 1 ´
10-19 nm b- 1 ´
10-15 nm c- 1 ´ 10-1
nm d- 1 ´
10-10 nm
A2- The
smallest value of the following is?
a- 0.03 mm b- 3 µm c- 0.3 nm d- 3000 pm
A3- The number of neutrons
(n) and protons (p) in the zinc element
is:
a- 30 n, 28 p b- 35 n, 30 p c-
31 n, 30 p d- 35 n, 28 p
A4- The appropriate symbol for the isotope with Z = 51 and A = 122
is
a-
b-
c-
d-
A5- Use the following table and choose which of the species are
neutral?
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atom or ion of
element
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A
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B
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C
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D
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E
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F
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Number of
electrons (e-)
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5
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10
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18
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10
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27
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2
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Number of
protons (p)
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5
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9
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16
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12
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29
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2
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Number of
neutrons (n)
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5
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9
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18
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12
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36
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1
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a- C and E b- B and C c- D and E d- A and F
A6- Chlorine has two stable isotopes;
and
. The number of protons in both isotopes is:
a- the same. b- smaller in
c- bigger in
. d- non of these.
A7- Atoms with the same number of protons and with different number
of neutrons are called
a- ions. b- neutral atoms c- isotopes. d-
different atoms.
A8- You have a 5.0 g sample of each of the following elements: Ca,
C, Be, Al. Which sample contains the most atoms?
a- Ca. b- C.
c- Be. d- Al
A9- Which of these pairs of elements would be most likely to form an
ionic compound?
a- P and C b- Cu and K c- C and O d- O and Zn
A10- Which one of these species is an ion?
a- B3+ b-
NaCl c-
He d- 14C
A11- What is the empirical formula of P4O10?
a-
P4O5 b- P2O5 c- PO d- PO5
A12- The correct name for N2O3 is
a- nitrogen trioxide b- dinitrogen trioxide
c- nitrogen oxide d- dinitrogen
oxide
A13- The correct name for Al2O3 is
a- aluminum(II) trioxide b- dialuminum trioxide
c- aluminum oxide d-
dialuminum oxide
A14- The Stock system name for CrSO3 is
a- chromium sulfide b- chromium(II) sulfate
c- chromium(II) sulfite d-
chromium(III) sulfite
A15- After balancing the following equation the coefficients are:
a C3H8 +
b O2 → c CO2 + d H2O
a-
a=1,
b=5, c=2, d=4 b- a=2, b=5, c=3, d=4
c-
a =1,
b=3, c=3, d=4 d- a=1, b=5, c=3, d=4
A16- The element nitrogen
consists of three isotopes: 13N, 14N, and 15N.
The atomic mass of nitrogen is 14.007 amu. Which isotope is more abundant?
a- 13N b- 14N c-
15N d-all the same
A17- Calculate the percent composition by mass of N in nitro toluoic
acid (C8H7NO4).
a- 3.87 % b- 53.04 % c- 7.73 % d- 35.36 %
A18- What is mass in grams of one atom of sulfur (S)?
a- 3.82 x 10-23 b- 5.31 x 10-23 c- 6.61 x 10-23 d- 1.05 x 10-22
A19- Calculate the number of O atoms in 2.50 g of sucrose (C12H22O11)
a- 3.87 x 1022 b- 4.84 x 1022 c- 5.81 x 1022 d- 6.78 x 1022
A20- Genes are considered to be composed of a
substance known as DNA. In a particular sample, the average mass of a DNA
molecule is 1.0 x 10-14 g. Calculate the molecular mass of DNA.
a- 6.02 x 108 b- 6.02 x 109 c- 6.02 x 107 d- 6.02 x 1010
A21- 0.90
g of a sample contains 0.83 g of carbon and 0.07 g
of hydrogen. What is the empirical formula of the compound?
a- C2H3 b- CH3 c-
CH2 d- CH
A22- An empirical formula
of an organic compound is C3H4O2, if the
molecular weight of the compound is (360 g/mol), the molecular formula of the
compound will be:
a-
C6H8O4 b- C12H16O8 c- C9H12O6 d- C15H20O10
A23- Iron(II) sulfate (FeSO4) is prescribed for the treatment of anemia.
How many moles of FeSO4 are present in a standard 500 mg tablet?
a- 1.64 x 10-3 b-
2.30 x 10-3 c- 3.29 x 10-3 d- 4.93 x 10-3
A24- Sodium metal and
water react to form sodium hydroxide and hydrogen gas. The mass of Na that will
react with excess of water
to produce 16.0 g NaOH is
2Na(s) + 2H2O(l)
→ H2(g) + 2NaOH(aq)
a- 5.75 g b- 6.90 g
c-8.05
g d- 9.20 g
A25- What mass of silver iodide (AgI) can be
produced by the reaction of 20.0 g of silver nitrate (AgNO3) with 20.0
g of sodium iodide (NaI)? AgNO3
(aq) +
NaI (aq) → AgI (s)
a- 13.82 g b- 27.65 g c- 41.47 g d- 55.29 g
A26- In an experiment, the actual yield was 7.05
g and the theoretical yield was 8.55 g, what is the percentage yield of the
product?
a- 84.80% b- 82.46% c- 80.12% d- 77.78%
A27- The number of grams of
sodium hydroxide (NaOH) required to prepare a 500 mL of a 0.1 M (NaOH)-solution
is:
a- 2.0 g b- 4.0 g c-
6.0 g d- 8.0 g
A28- In seawater, the
concentration of Na+ ions is about 0.46 M. What is the mass in gram
of Na+ ions are there in 2.5 L of seawater?
a- 15.9 g b- 21.2 g c- 26.5 g d- 31.7 g
A29- You have 500 mL of a 0.600 M HCl solution and you want to
dilute it to exactly 0.100 M. How much water should you add?
a- 250 mL b- 500 mL c- 1000 mL d- 2500 mL
A30- A 3.50 g sample of KClO3 is dissolved in enough water
to give 375 mL of solution. What is the chlorate ion concentration in this
solution?
a- 3.27 x 10-2M b-
5.44 x 10-2M c- 7.62 x 10-2 d- 9.80 x 10-2M
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