198. In a photoelectric experiment, the longest wavelength that can separate an electron from a metal plate is 480 nanometers. What wavelength (in nanometers) of light with a voltage cut-off of 1.5 volts?
\[ \left(C = 3\times10^{8}\ \frac{\text{m}}{\text{s}},\ h = 4\times10^{-15}\ \text{eV.s}\right) \]
\[ \text{(1)}\ 300 \qquad \text{(2)}\ 350 \qquad \text{(3)}\ 400 \qquad \text{(4)}\ 450 \]

199. The half-life of a substance is 8 days. After 32 days, what percentage of the nuclei of that substance remain?
\[ \text{(1)}\ 6.25 \qquad \text{(2)}\ 75 \qquad \text{(3)}\ 87.50 \qquad \text{(4)}\ 93.75 \]

200. In the nuclear reaction ${}^{137}_{55}\text{Cs} \rightarrow {}^{137}_{56}\text{Ba} + X$, the mass difference is $0.005\ \text{u}$ and each atomic mass unit equals $1.7\times10^{-27}$ kilograms. $X$ is which particle and how many joules of energy is released?
\[ \left(C = 3\times10^{8}\ \frac{\text{m}}{\text{s}}\right) \]
\[ \text{(1)}\ e^{-},\ 5.1\times10^{-22} \qquad \text{(2)}\ e^{+},\ 5.1\times10^{-22} \] \[ \text{(3)}\ e^{-},\ 1.53\times10^{-13} \qquad \text{(4)}\ e^{+},\ 1.53\times10^{-13} \]
[Calculation space]
%% Page 19 Chemistry 120-C Page 18

201- If the electron in a hydrogen atom is excited from the ground state to the level $n = 5$, which statement is correct?

1. [(1)] For the ionization of this atom, less energy is needed compared to the ground state.
2. [(2)] The electron in this state has less energy compared to the ground state and is farther from the nucleus.
3. [(3)] The wavelength of the emitted light when returning to the ground state is greater than that for returning to $n = 2$.
4. [(4)] The energy required to remove this electron from the atom is the ionization energy of the first shell of hydrogen.

202- The twenty-first electron of the atom ${}^{\ }_{25}\mathrm{Mn}$, according to the Aufbau principle, belongs to which set of quantum numbers?
\begin{align*} &(1) n = 3,\ l = 2,\ m_l = -1,\ m_s = +\tfrac{1}{2} &(2) n = 3,\ l = 2,\ m_l = -2,\ m_s = +\tfrac{1}{2} &(3) n = 4,\ l = 2,\ m_l = -1,\ m_s = -\tfrac{1}{2} &(4) n = 4,\ l = 2,\ m_l = -2,\ m_s = -\tfrac{1}{2} \end{align*}

203- How many electrons must be removed from the surface of a plastic ball by friction so that its weight change can be measured with a sensitivity of $0.1$ milligrams, and approximately how many coulombs of electric charge does this number of electrons carry? (The charge of an electron is approximately $1.6 \times 10^{-19}$ C and $g \approx 9 \times 10^{-28}$ g.)
\begin{align*} &(1) 1.78\times10^{5}, 3/011\times10^{22} &(2) 1.66\times10^{4}, 1/11\times10^{22} &(3) 1.648\times10^{5}, 3/011\times10^{22} &(4) 1.78\times10^{4}, 1/11\times10^{22} \end{align*}

204- Which of the following statements about halogens is correct?

• The largest atomic radius is comparable to elements of the same period.
• In reaction with all alkaline earth metals, they form ionic compounds.
• With increasing atomic number, their reactivity and bond energy decrease.
• The acidic property of their compounds with hydrogen (HX) decreases with increasing atomic number.

(1) 1 (2) 2 (3) 3 (4) 4

205- If the electronic configuration ends with $1s^2$, which of the following statements about it is correct?

• The related element is only in the first period of the periodic table.
• The related element can be placed in the first group of the periodic table.
• Such an element can be connected to the anion of alkaline earth metals.
• The related element can have the highest ionization energy among elements.

(1) 1 (2) 2 (3) 3 (4) 4
%% Page 20 Chemistry 120-C Page 19

206- What is the effect of the shielding of inner electrons on the outermost electron layer of an atom? In which case does it have more influence?

1. [(1)] Geometric shape of molecules
2. [(2)] Reactivity of sodium element
3. [(3)] Type of number of relaxation phases in intermediate phases
4. [(4)] Boiling point of fluorine compared to elements of the same period

207- The ratio of the number of bonding electrons to the number of non-bonding electrons in the glucose molecule is which of the following?
(1) $4$ (2) $2$ (3) $2.5$ (4) $2$

208- The electronegativity of oxygen is $3.5$ and the electronegativity difference of it with bond $\text{S}-\text{I}$ is $1$. Given that the bond $\text{O}-\text{S}$ is polar, the bond $\text{S}-\text{O}$ is ............... and the electronegativity of sulfur can be ...............

1. [(1)] Polar -- equal to $2.5$.
2. [(2)] Nonpolar -- equal to $2.5$.
3. [(3)] Polar -- differ from the electronegativity of oxygen by $0.5$ units.
4. [(4)] Nonpolar -- differ from the electronegativity of oxygen by $0.5$ units.

209- Which of the following statements are correct?

• [A)] Three-atom molecules can be linear, having one of two geometric shapes.
• [B)] Compounds whose chemical formula is similar to stoichiometry have the same shape.
• [C)] The geometric shape of a molecule is one of the important factors in determining the chemical and physical properties of it.
• [D)] All molecules whose atoms forming the molecule are unequal in number, their geometric shapes are different.

(1) A, D (2) B, D (3) B, C (4) A, B, C

210- Which of the following statements are correct?

• [A)] Acrylic fibers are prepared from polymerization of acrylonitrile.
• [B)] Plastic materials are polymers that are prepared from polymerization of alkenes.
• [C)] Production of biodegradable polymers is a more appropriate solution to reduce environmental problems.
• [D)] One of the alkenes is used to help ripen some fruits such as tomatoes and bananas.
• [E)] Most containers that are made of polymers are correct, but the materials stored in them have a negative effect on them.

(1) B, D, E (2) B, C, D (3) A, D, C (4) A, B, E
%% Page 21
120-C Page 20 [6pt] Chemistry

211. Regarding the compound shown below, which of the following statements are correct?
[Figure: Organic compound with COOH group, NH group, $\text{OCH}_\gamma$ group, $\text{H}_2\text{N}$ group, and a cyclopentane ring with a ketone]

• It has two amine groups.
• 6 atoms in it have three electron pairs.
• Its structure has only one alpha-amino acid.
• Its saponification product is obtained under alkaline conditions.
• It has one carboxyl functional group and one steric functional group.

(1) 1 (2) 2 (3) 3 (4) 4

212. How many grams of oxygen gas released from the thermal decomposition of 3/0 mol of potassium chlorate can be obtained, assuming both reactions are 100\% efficient? $(N = 14,\ O = 16,\ Na = 23:\ \text{g.mol}^{-1})$
(1) $36$ (2) $41$ (3) $68$ (4) $76/5$

213. In a car tire, 13 g of sodium azide has been used. If after the explosion, the temperature inside the tire reaches $127^\circ\text{C}$, the volume of gas inside the tire increases to approximately how many liters? (Assume the gas pressure inside the tire is 1 atmosphere.) $(N = 14,\ Na = 23:\ \text{g.mol}^{-1})$
(1) $6/77$ (2) $8/75$ (3) $9/85$ (4) $11/50$

214. If a solution of silver chloride contains 2/7 g of this salt with sufficient silver nitrate solution, 5/74 g of silver nitrate precipitate forms. What is the molar mass of this metal relative to its capacity? $(Cl = 35/5,\ Ag = 108:\ \text{g.mol}^{-1})$
(1) $67/5$ (2) $54$ (3) $46$ (4) $33$

215. For the reaction: $\text{PH}_3(\text{g}) + \text{O}_2(\text{g}) \rightarrow \text{P}_4\text{O}_{10}(\text{s}) + \text{H}_2\text{O}(\text{l})$, after balancing, what is the difference between the sum of the stoichiometric coefficients of the reactants and the sum of the stoichiometric coefficients of the products? If the percent yield of this reaction is 85\%, and 1/6 mol $\text{PH}_3$ is consumed, how many moles of $\text{P}_4\text{O}_{10}$ are obtained?
(1) displacement: 4, reduction: 0/64 (2) oxidation -- reduction: 5, 0/64
(3) displacement: 5, reduction: 0/34 (4) oxidation -- reduction: 4, 0/34

216. If 50 mL of 0/6 mol NaOH solution is mixed with 150 mL of 0/1 mol $\text{H}_2\text{SO}_4$ solution at $25^\circ\text{C}$ inside a calorimeter, and the temperature at the end of the reaction reaches $30^\circ\text{C}$, $\Delta H$ of the reaction: $$2\text{NaOH}(\text{aq}) + \text{H}_2\text{SO}_4(\text{aq}) \rightarrow \text{Na}_2\text{SO}_4(\text{aq}) + 2\text{H}_2\text{O}(\text{l})$$ is approximately how many kilojoules? (Assume the heat of the reaction is only used to raise the temperature of the water, and $c_p = 4/2\ \text{J.g}^{-1}.^\circ\text{C}^{-1}$ for all solutions. Assume density $1\ \text{g.mL}^{-1}$.)
(1) $+150$ (2) $-150$ (3) $+785$ (4) $-785$
\begin{flushright} Calculation space \end{flushright}
%% Page 22 Chemistry 120-C Page 21

217- Considering the reactions below, how many kilojoules of energy must be consumed to produce one kilogram of water vapor?
$$(O = 16,\ C = 12,\ H = 1 : \text{g.mol}^{-1})$$
$$C(\text{s, graphite}) + O_2(\text{g}) \rightarrow CO_2(\text{g}) \quad , \quad \Delta H = -394\text{ kJ}$$
$$CO(\text{g}) + \frac{1}{2}O_2(\text{g}) \rightarrow CO_2(\text{g}) \quad , \quad \Delta H = -283\text{ kJ}$$
$$2H_2(\text{g}) + O_2(\text{g}) \rightarrow 2H_2O(\text{g}) \quad , \quad \Delta H = -490\text{ kJ}$$

(1) $11833$		(2) $14400$
(3) $4446.7$		(4) $6745.2$

218- For which reaction can $\Delta H$ be considered as the standard enthalpy of formation of the product?

(1) $H_2(\text{g}) + O_2(\text{g}) \rightarrow H_2O_2(\text{l})$	(2) $SO_3(\text{g}) + H_2O(\text{l}) \rightarrow H_2SO_4(\text{l})$
[6pt] (3) $2F_2(\text{g}) + O_2(\text{g}) \rightarrow 2OF_2(\text{g})$	(4) $Mg(\text{g}) + \dfrac{1}{2}O_2(\text{g}) \rightarrow MgO(\text{s})$

219- Considering the reaction: $Pb(\text{s}) + PbO_2(\text{s}) + 2H_2SO_4(\text{aq}) \rightarrow 2PbSO_4(\text{s}) + 2H_2O(\text{l})$, if 35 grams of lead is consumed in this reaction, how many kilojoules of energy are released? ($Pb \approx 207\ \text{g.mol}^{-1}$)

Compound	$H_2SO_4(\text{aq})$	$PbO_2(\text{s})$	$H_2O(\text{l})$	$PbSO_4(\text{s})$
$\Delta H_f$ (kJ)	$-814$	$-277$	$-286$	$-918$

(1) $1385$

(2) $1505$

(3) $1881$

(4) $2515$

220- How many of the following statements are correct?

• Dissolving every salt in water is accompanied by absorption of heat and cooling of the solution.
• Increasing pressure, contrary to its effect on the solubility of gases, increases the solubility of gases with temperature.
• Dissolving gases such as oxygen and nitrogen in water, unlike dissolving salts in water, is accompanied by a decrease in entropy.
• Increasing pressure, contrary to its effect on the solubility of gases, increases the solubility of some salts such as sodium nitrates with temperature.

(1) 1

(2) 2

(3) 3

(4) 4

%% Page 23
120-C Page 22

221- Which of the following statements is correct? $(H = 1,\ C = 12,\ O = 16,\ Na = 23\ :\ \mathrm{g.mol^{-1}})$

• Acetone is a colorless liquid whose solubility in water is low.
• Insoluble substances are materials whose solubility is said to be zero.
• The reason vitamin A does not dissolve in water is that the polar part of its molecule dominates.
• In a mixture of 0.1 mol 1-butanol with 1000 g of water, only one phase is observed. (The solubility of this alcohol under experimental conditions is 2.7 g per 100 g of water.)

(1)\ 1 (2)\ 2 (3)\ 3 (4)\ 4

222- A silver nitrate solution with a molar mass of 80 g/mol and a concentration of $1.2\ \mathrm{g.mL^{-1}}$ at a certain temperature is prepared. The molar concentration is $2.5\ \mathrm{mol.L^{-1}}$. If at the same temperature the vapor pressure equals $2.5\ \mathrm{mol.L^{-1}}$, how many grams of water are in 100 g of the solution?
(1)\ 35 (2)\ 24 (3)\ 50 (4)\ 16