71. According to the figure, three immiscible liquids are poured into a tube. Which relationship between the pressures at the marked points is correct?
[Figure: A U-shaped tube with three immiscible liquids; points A, B, C, D are marked at various levels in the tube.]

1. [(1)] $P_A > P_B > P_C = P_D$
2. [(2)] $P_A = P_B > P_C > P_D$
3. [(3)] $P_A - P_C = P_B - P_D$
4. [(4)] $P_A + P_C = P_B + P_D$

72. In a pressure cooker, the area of the steam outlet is $5\,\text{mm}^2$. What should the mass of the weight placed on the outlet be so that the steam pressure inside the cooker reaches $1.5 \times 10^5$ pascals? $\left(g = 10\,\dfrac{\text{m}}{\text{s}^2}\right)$
(1) $25$ (2) $25$ (3) $40$ (4) $50$
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73 -- In the figure below, the total mass of the tractor and its load is 2 tons, and the tractor moves on a slope at angle $37^\circ$. A constant force of $6000\,\text{N}$ is applied to it. If the friction force applied to the tractor is $4000\,\text{N}$, and with this condition the tractor moves 5 meters horizontally and vertically along the slope, how many joules does the lateral kinetic energy of the tractor change? ($\cos 37^\circ = 0.8$)
[Figure: A tractor pulling logs on a slope]

• [(1)] $4000$
• [(2)] $20000$
• [(3)] $24000$
• [(4)] $44000$

74 -- $80\,\text{g}$ of water at $25^\circ\text{C}$ together with $20\,\text{g}$ of water at $80^\circ\text{C}$ are poured into a metal container of mass $300\,\text{g}$ at $32^\circ\text{C}$. What is the equilibrium temperature in degrees Celsius? ($c_{\text{metal}} = 400\,\dfrac{\text{J}}{\text{kg.K}}$ and $c_{\text{water}} = 4200\,\dfrac{\text{J}}{\text{kg.K}}$)
$$50 \;(1) \qquad 42 \;(2) \qquad 40 \;(3) \qquad 32 \;(4)$$

75 -- In the figure below, a piston of mass $1.75\,\text{kg}$ and base area $50\,\text{cm}^2$ is placed on an ideal gas in equilibrium. If a mass 9 times the piston's mass is placed on it, the piston moves down to a height of $10\,\text{cm}$ and reaches equilibrium again.
[Figure: A vertical cylinder with a piston, height labeled $40\,\text{cm}$]
If the temperature of the gas remains constant, what is the air pressure in pascals? ($g = 10\,\dfrac{\text{m}}{\text{s}^2}$)

• [(1)] $1.1 \times 10^5$
• [(2)] $1.2 \times 10^5$
• [(3)] $9.1 \times 10^4$
• [(4)] $9.6 \times 10^4$

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76-- If the electron configuration of atom $^{96}X$ resembles the electron configuration of the capacity atom of the twenty-fourth element of the periodic table, and the number of electrons in one of its stable ions equals the number of electrons in the first atom of the first period of the fifth period of the periodic table, what is the number of neutrons in atom $X$?
$52\ (1) \qquad\qquad 54\ (2) \qquad\qquad 56\ (3) \qquad\qquad 58\ (4)$

77-- Which case is incorrect?

1. The line emission spectrum of each element is a means of identifying that element.
2. In the visible region, the number of colored lines in the emission spectrum of lithium equals the emission spectrum of hydrogen.
3. One of the applications of line emission spectra in ``food quality control and food adulteration'' is related to food products.
4. By observing the change in flame color due to dissolving a salt solution, one can identify the type of metal element present in it.

78-- If element $X$ and element $_{28}$Ni are in the same period and in the same group, and are constructed as nuclear reactor elements, the electronic configuration of its cation in the compound .................. is of the form ....................
$[_{18}Ar]3d^54s^2\ ,\ X_rO_r\ (1) \qquad\qquad [_{18}Ar]3d^54s^2\ ,\ XCl_r\ (2)$
$[_{18}Ar]3d^4\ ,\ XCl_r\ (3) \qquad\qquad [_{18}Ar]3d^4\ ,\ X_rO_r\ (4)$

79-- Which case is correct?

1. More than 75\% of the infrared radiation emitted from the sun toward Earth is absorbed in the stratosphere by the ozone layer.
2. In the Haber process, for the separation of nitrogen from hydrogen, the mixture including the products is cooled to about $-200^\circ$C.
3. The percentage by volume of nitrogen gas in the air is approximately $0.95$ of the total gas in a car's tire.
4. Nitrogen gas is the most abundant component of the atmosphere and has no industrial applications.

80-- $N_2$ and $O_2$ gases react completely with each other under suitable conditions. If the mass difference of the two gases at the start of the reaction is 0.125 grams, NO (as the only product of the reaction) is formed, and from this reaction the amount of NO gas formed --- with a sufficient amount of oxygen gas --- how many liters of $NO_2$ gas are formed at STP?
$(N{=}14,\ O{=}16\ :\ \text{g.mol}^{-1})$
$2/8\ ,\ 3/75\ (1) \qquad\qquad 1/4\ ,\ 3/75\ (2) \qquad\qquad 7/8\ ,\ 1/875\ (3) \qquad\qquad 1/4\ ,\ 1/875\ (4)$

81-- Which case is correct?

1. Gases, unlike solids and liquids, have no definite volume or shape.
2. By increasing the pressure on a gas sample, the volume of its molecules decreases.
3. The distance between molecules of a gas sample is a function of the pressure exerted on it.
4. At constant temperature and pressure, the volume of one gram of gas CO equals the volume of one gram of gas $CO_2$.

Calculation Space
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82 -- Considering the given reaction, if 250 milliliters of $\text{Ba(OH)}_2$ solution with a concentration of 21375 ppm is present, how many milliliters of 0.4 molar $\text{HCl}$ solution are needed for the complete reaction with it? (Assume the density of the solution equals the density of water; $\text{H}{\blacksquare}1$, $\text{O}{\blacksquare}16$, $\text{Ba}{\blacksquare}137$ : $\text{g.mol}^{-1}$)
$$\text{Ba(OH)}_2(aq) + \text{HCl}(aq) \longrightarrow \text{BaCl}_2(aq) + \text{H}_2\text{O}(l)$$
(1) $37.5$ (2) $62.5$ (3) $75$ (4) $125$

83 -- Considering the properties of water and hydrogen sulfide molecules, which statement is correct?

1. The difference in intermolecular attractive forces is the most important factor in the difference in their boiling points.
2. The difference in molecular structure is one of the most important factors determining the difference in boiling points of the two molecules.
3. The difference in atomic radii and molar mass of central atoms plays a role in determining the difference in boiling points of the two molecules.
4. The polarity difference of the two molecules, like the polarity difference of $\text{CS}_2$ and $\text{CO}_2$ molecules, plays no role in determining their boiling points.

84 -- Which of the following is correct?
A: In stable ions of main-group metals, the number of electrons in all sub-shells is even.
B: Stable ions formed from atoms $_{31}\text{Ga}$ and $_{30}\text{Zn}$ have similar electron configurations.
C: The color of vanadium salt solution changes from yellow to purple upon reaction with iron metal dust.
D: The use of plants that absorb metals is one of the appropriate methods for extracting nickel, copper, and gold.
(1) ``A'' and ``C'' (2) ``A'' and ``B'' (3) ``B'' and ``D'' (4) ``B'' and ``D''

85 -- If A, D, and M are three noble gas-shaped substances and in the reaction: $\text{A} + \text{D} \longrightarrow \text{M} + \text{H}_2\text{O}(l)$, a solution is converted into a mixture of these three substances, which comparison about the dissolution of these three substances is always correct?
(1) $M < A < D$ (2) $A > M > D$ (3) $M < A, D$ (4) $M > A, D$

86 -- The sum of stoichiometric coefficients of substances in the following balanced reaction, after consuming 82.8 grams of $\text{NaNO}_2$ and

87 -- Which statement is correct?

1. Providing a basic environment is one of the conditions for producing ethanol from ethene.
2. The feasibility of the alkene reaction with bromine liquid and the formation of saturated carbon molecules depends on the number of carbon molecules of the alkene.
3. If the boiling point of crude oil is known, one can comment on the physical state of white oil.
4. In fractional distillation of crude oil, with increasing altitude, the trend of temperature changes and the size of exiting molecules are opposite to each other.

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88 -- Considering the thermochemical reaction: $\Delta H = \blacksquare\blacksquare\blacksquare +65 \text{ kJ}$, $2\text{CH}_2(g) \longrightarrow \text{C}_2\text{H}_4(g) + \text{H}_2(g)$, the average enthalpy of the $\text{C}{=}\text{H}$ bond per mole is how many kilojoules? (The enthalpies of $\text{H}{-}\text{H}$ and $\text{C}{=}\text{C}$ bonds are 435 and 348 kJ per mole, respectively.)
(1) $442$ (2) $424$ (3) $412$ (4) $422$

89 -- How many of the following statements about elements of the periodic table are correct?

• If element A is a metalloid, it certainly belongs to the p-block of the periodic table.
• The atomic number of a nonmetal element is certainly greater than that of its group members.
• If element Z is a liquid nonmetal, it has no period with high chemical activity.
• If element X is a metalloid, all elements in the same period and with a smaller atomic number than it have physical properties of metals.

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

90 -- In a two-liter closed container, $0.2$ mol of ammonia gas and $0.25$ mol of oxygen gas react. If the reaction rate is constant and equal to $0.02\ \text{mol·L}^{-1}\text{·min}^{-1}$, after $30$ seconds, how many moles of gas are in the container and how many seconds until the reaction is complete?
$$\text{NH}_3(g) + \text{O}_2(g) \longrightarrow \text{NO}(g) + \text{H}_2\text{O}(g)$$ (Balance the reaction equation.)
(1) $30,\ 0.47$ (2) $45,\ 0.47$ (3) $30,\ 0.38$ (4) $45,\ 0.38$

91 -- How many of the following statements are correct?

• Reaction rate is a useful concept for understanding the rate of reaction progress per unit time.
• The average rate of formation of a product equals its stoichiometric coefficient multiplied by 1.
• The slope of the ``mole–time'' graph for each participant in a reaction is proportional to its stoichiometric coefficient.
• Reaction rate is obtained by dividing the average rate of consumption or production of each substance in the reaction by its stoichiometric coefficient.

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

92 -- Which statement is correct?

1. [(1)] The number of glucose units in the molecules of fiber-forming polymers is equal.
2. [(2)] From the perspective of molar mass, olive oil can be considered intermediate between polyatonin and insulin.
3. [(3)] In the structure of polyacrylonitrile, polytetrafluoroethylene, and polyvinyl chloride, non-bonding electron pairs exist.
4. [(4)] Natural polymers, like synthetic polymers, are formed through covalent bonds between their monomer units.

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93. In the following cases, in what order have the methods been used to increase the reaction rate?
``Adding $\text{Fe}^{3+}\text{(aq)}$ to hydrogen peroxide solution for its decomposition, preserving iron fibers in oxygen, burning iron powder on a flame''

1. Using a catalyst, increasing surface area of contact, increasing temperature
2. Increasing concentration of reactants, increasing temperature, increasing surface area of contact
3. Increasing concentration of reactants, increasing surface area of contact, increasing temperature
4. Using a catalyst, increasing concentration of reactants, increasing surface area of contact

94. Regarding the compound with the structure shown below, which of the following is correct?
[Figure: A bicyclic compound containing a benzimidazole ring fused with a benzene ring, connected via a sulfinyl group ($S=O$) to a side chain containing a pyridine-like ring with methyl substituents and a ketone group ($C=O$)]
A: The number of $\mathbf{C{\equiv}H}$ bonds equals the number of carbon atoms in it.
B: If the nitrogen atoms are replaced by carbon atoms, a structure with three benzene rings is formed.
C: The number of carbon atoms in the molecule, with the number of these atoms in 3 nonane and 6 methyl nonane molecules, is equal.
D: The number of double bonds between atoms equals twice the number of lone pairs on the most electronegative atom in the structure.

1. ``A'' and ``C''
2. ``A'' and ``D''
3. ``B'' and ``C''
4. ``B'' and ``D''

95. Which case is correct?

1. In the equilibrium solution of hydrofluoric acid, $[\text{H}^+]$ is constant and equal to $[\text{HF}]$.
2. In the ionic dissociation of hydrogen chloride gas in water, ammonium ion and chloride ion are formed at equal concentrations.
3. At equal molar concentrations, the acidity of formic acid solution is less than that of acetic acid solution.
4. If $[\text{H}^+]$ in solution HA is less than $[\text{X}^-]$ in solution HX, then the pH of solution HX is greater than the pH of solution HA.