198- In a hydrogen atom, the electron transitions from level $n=1$ to level $n=3$. In this transition, the orbital radius and the electron's energy, respectively, become how many times the previous state?
(1) $3$ and $\dfrac{1}{3}$ (2) $9$ and $\dfrac{1}{9}$ (3) $3$ and $3$ (4) $9$ and $9$

199- Which of the following statements about the band structure of amorphous solids is correct?

1. [(1)] After the last full band, a half-full band (partially filled) exists.
2. [(2)] The number of electrons present in the conduction band is very large.
3. [(3)] The energy gap between the last full band and the first empty band is large and about 5 electron volts.
4. [(4)] The energy gap between the last full band and the first empty band is small and about 1 electron volt.

200- In a nuclear reaction, 2 milligrams of mass is converted to energy. The energy produced is equivalent to how many kilowatt-hours? $\left(C = 3\times10^{8}\ \dfrac{\text{m}}{\text{s}}\right)$
(1) $2.5\times10^{4}$ (2) $2.5\times10^{9}$ (3) $5\times10^{4}$ (4) $5\times10^{9}$

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201- Which option is incorrect?

1. [(1)] In the ionization energy diagram of element $_{19}$K, three large jumps are observed.
2. [(2)] Linear emission spectra of elements played a role in the discovery of rubidium and cesium elements.
3. [(3)] The first ionization energy of elements $_{5}$B, $_{4}$Be, and $_{6}$C increases in the order $B < Be < C$.
4. [(4)] In the emission spectrum of hydrogen, red light has the greatest deviation from the initial path when passing through a prism.

202- Which option is correct?

1. [(1)] In the atom $_{22}$Ti, only two electrons have the set of quantum numbers $n=3$, $l=2$, and $m_s = +\dfrac{1}{2}$.
2. [(2)] The principal quantum number $n$ was first proposed by Schr\"{o}dinger to calculate the energy of electrons in an atom.
3. [(3)] The number of electrons with spin $+\dfrac{1}{2}$ in atom $_{30}$Zn differs from that in atom $_{24}$Cr.
4. [(4)] The emission line spectrum of the hydrogen atom was first discovered by Henry Moseley.

203- If the mass of a proton is 1840 times the mass of an electron, the mass of a neutron is 1850 times the mass of an electron, and the mass of an electron is $0.000054$ amu, given that $1\ \text{amu} = 1.66\times10^{-24}\ \text{g}$, the approximate mass of one tritium atom will be how many grams?

1. [(1)] $4.96\times10^{-24}$
2. [(2)] $9.112\times10^{-24}$
3. [(3)] $4.34\times10^{-22}$
4. [(4)] $9.815\times10^{-22}$

204- Considering that atom A from period three forms ionic compounds with Cl and O having formulas ACl and $\text{A}_2\text{O}$, and atom X from the same period forms ionic compounds with N and F having formulas $\text{X}_3\text{N}_2$ and $\text{XF}_2$, which option is correct?

1. [(1)] Atom A has electrons with quantum number $l=2$, and atom X does not.
2. [(2)] The second ionization energy of atom A is greater than the second ionization energy of atom X.
3. [(3)] A is an element from group IB and X is an element from group IA of the periodic table.
4. [(4)] A dissolved in water and X dissolved in water both form hydroxide solutions.

205- Element $_{M}$A with element ......... are in the same group in the periodic table, and the last and outermost occupied subshell of that atom, ......... is and ......... comes out to be calculated.

1. [(1)] $_{44}$X, semi-metal, $4\text{p}^4$ (2) $_{22}$Y, non-metal, $4\text{p}^2$ (3) $_{44}$X, semi-metal, $5\text{p}^4$ (4) $_{22}$Y, semi-metal, $5\text{p}^2$, non-metal

206- Referring to the figure below, A, B, and C indicate the lattice energies of which halide compounds, and with larger cations of the same group, the lattice energy of the network changes more? (Read the options from right to left.)
[Figure: Graph of lattice energy (kJ/mol) vs. halide ions $\text{F}^-$, $\text{Cl}^-$, $\text{Br}^-$, $\text{I}^-$, showing three curves A, B, C decreasing from approximately 1100, 800, 700 to 600 kJ/mol respectively]

1. [(1)] K, Na and F, Li
2. [(2)] Na, Li and K, I
3. [(3)] Li, Na and K, F
4. [(4)] K, Na and Li, I

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207- If 0.1 mol of the salt $\mathrm{Na_2SO_4 \cdot 8H_2O}$ is heated and its weight decreases by approximately 18.9 percent, $x$ in the chemical formula of the remaining solid $(\mathrm{Na_2SO_4 \cdot xH_2O})$ is approximately which of the following?
$$(\mathrm{Na = 23\ ,\ S = 32\ ,\ O = 16\ ,\ H = 1 : g.mol^{-1}})$$
(1) 3 (2) 4 (3) 5 (4) 6

208- The presence of non-bonding electron pairs on the central atom of a molecule has less effect on which of the following?
(1) Molecular polarity (2) Bond angles (3) Molecular geometry (4) Bond length

209- In which molecule, the ratio of the number of bonding electron pairs in the non-bonding layer of atoms to the number of bonding electron pairs is greater than the other three compounds?
(1) Xenon(IV) fluoride (2) Nitrogen trifluoride (3) Sulfur trioxide (4) Carbon disulfide

210- In naming alkanes, which carbon atoms of the main chain can be numbered from both ends of the chain?
(1) 3, 2 — di methyl — 2 — pentene (2) 4, 2 — di methyl — 2 — hexene
(3) 4, 2 — di methyl — 2 — pentene (4) 5, 2 — di methyl — 3 — hexene

211- If in the methanol molecule, the oxygen atom is replaced by the group $\mathrm{C=O}$, which compound is obtained and how many electrons in that molecule participate in pi bonding?
(1) Ketene $-$ 6 (2) Ketene $-$ 4 (3) Methanoic acid $-$ 6 (4) Methanoic acid $-$ 4

212- 24.5 grams of sulfuric acid is mixed with 0.2 mol of aluminum phosphate and they react with each other to the limiting extent, and approximately how many grams of phosphoric acid is formed?
$$(\mathrm{H = 1,\ O = 16,\ P = 31,\ S = 32 : g.mol^{-1}})$$
(1) Sulfuric acid, 24.5 (2) Sulfuric acid, 16.3 (3) Aluminum phosphate, 19.6 (4) Aluminum phosphate, 29.4

213- In 25 mL of a 34 percent by mass ammonia solution with a density of $0.98\ \mathrm{g.mL^{-1}}$, how many moles of ammonia are present and what is the molarity of this solution? (Read the options from right to left.) $(\mathrm{H = 1,\ N = 14 : g.mol^{-1}})$
(1) $15/7 \circ /49$ (2) $19/6 \circ /49$ (3) $15/7 \circ /52$ (4) $19/6 \circ /52$

214- To prepare 14.2 liters of chlorine gas from the reaction of manganese dioxide with hydrochloric acid, how many grams of 75\% pure manganese dioxide are needed? (The density of chlorine gas at experimental conditions is $1.25\ \mathrm{g.L^{-1}}$.)
$$(\mathrm{O = 16,\ Cl = 35.5\ ,\ Mn = 55 : g.mol^{-1}})$$
(1) 27 (2) 28.5 (3) 29 (4) 30.8

215- $9.033 \times 10^{23}$ iron atoms are present and react with sufficient sulfuric acid, how many liters of hydrogen gas are produced? (The density of hydrogen gas at reaction conditions is $0.08\ \mathrm{g.L^{-1}}$. Read the options from right to left.)
(1) $4/5 \circ /18$ (2) $3/9 \circ /18$ (3) $3/25 \circ /15$ (4) $3/75 \circ /15$

216- If $\Delta H^\circ$ of combustion of methanol is $-700\ \mathrm{kJ.mol^{-1}}$, how many grams of it must be burned so that the released heat can bring 125 grams of water from $10^\circ\mathrm{C}$ to boiling at 1 atm pressure?
$$\left(\mathrm{c_{(water)} = 4.2\ J.g^{-1}.{}^\circ C^{-1},\ O = 16,\ C = 12,\ H = 1 : g.mol^{-1}}\right)$$
(1) $2/16$ (2) $1/68$ (3) $2/52$ (4) $3/36$
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217. $\Delta H$ of the reaction: $2\text{HCN}(g) + 6\text{H}_2\text{O}(l) \rightarrow 2\text{NH}_3(g) + 2\text{CH}_4(g) + 3\text{O}_2(g)$ is equal to how many kilojoules, and if $8.5\ \text{g}$ of ammonia participates in the reaction, how many kilojoules of heat are released for the formation of $\text{CH}_4(g)$, $\text{NH}_3(g)$, and $\text{HCN}(g)$ and $\text{H}_2\text{O}(l)$? Take the enthalpies of formation as $-46$, $-75$, $-50$, $+130/5$, and $-286$ kJ per mole respectively.
$(H = 1,\ N = 14\ :\ \text{g.mol}^{-1})$

(1) $202/25, -1213$ (2) $303/25, -1213$ (3) $245/35, -1313$ (4) $345/35, -1313$

218. Which option is incorrect? (Consider the specific heat capacities of water and copper to be $4.2$ and $0.4\ \text{J}$ per gram per degree Celsius respectively.)

1. The specific heat capacity of every substance is independent of its bonding amount.
2. The specific heat capacity of $9\ \text{g}$ of water is $10$ times the specific heat capacity of $9.45\ \text{g}$ of copper at the same temperature.
3. Thermodynamics is the study of the transformation of various forms of energy into one another and the ways of transferring them.
4. The specific heat capacity of one cubic centimeter of water vapor is greater than that of liquid water at room temperature and pressure.

219. Given the following reactions:
$$\text{a)}\ \text{O}_2(g) + 2\text{ClF}(g) \rightarrow \text{Cl}_2\text{O}(g) + \text{OF}_2(g) \quad,\quad \Delta H = +168\ \text{kJ}$$
$$\text{b)}\ \text{O}_2(g) + 2\text{F}_2(g) \rightarrow 2\text{OF}_2(g) \quad,\quad \Delta H = -44\ \text{kJ}$$
$$\text{c)}\ 2\text{ClF}_3(l) + 2\text{O}_2(g) \rightarrow \text{Cl}_2\text{O}(g) + 3\text{OF}_2(g) \quad,\quad \Delta H = +394\ \text{kJ}$$
$\Delta H$ of the reaction producing $\text{ClF}_3(l)$ from gases $\text{ClF}$ and $\text{F}_2$ is how many kilojoules?

(1) $-135$ (2) $-270$ (3) $+518$ (4) $+259$

220. If the density of a sample of 6 molar sulfuric acid solution is $1.5\ \text{g.mL}^{-1}$, what is its approximate molality?
$(H = 1,\ O = 16,\ S = 32\ :\ \text{g.mol}^{-1})$

(1) $6/58$ (2) $6/8$ (3) $5/25$ (4) $5/46$

221. Which option is correct? $(H = 1,\ C = 12,\ O = 16\ :\ \text{g.mol}^{-1})$

1. Alkaline earth metal carbonates, like alkali metal carbonates, dissolve in water.
2. A mixture of water and barium sulfate and acetone has two common phases.
3. The molar mass difference between phenol and toluene equals the molar mass difference between methanol and ethanol.
4. The solubility of ethanol in nonpolar solvents is greater than that of hexanol in those solvents.

222. $8.4\ \text{g}$ of potassium hydroxide $(M = 56\ \text{g.mol}^{-1})$ is added to $150\ \text{g}$ of water. If the initial temperature of all substances is $25^\circ\text{C}$ and the specific heat capacities of water and potassium hydroxide solution are $4.2$ and $1\ \text{J}$ per gram per degree Celsius respectively, and the system reaches equilibrium at $40^\circ\text{C}$, what is the approximate enthalpy of dissolution of KOH in $\text{kJ.mol}^{-1}$? (Heat absorbed by the calorimeter is neglected.)

(1) $59/8$ (2) $56$ (3) $63/8$ (4) $75$

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