200- According to the figure below, for a fixed amount of ideal gas going from state A to state C via two paths, if the increase in internal energy of the gas from A to C is $1000\,\text{J}$, how many joules of heat does the gas absorb along path ABC?
[Figure: P-V diagram with points A, B, C; B at pressure $2\times10^5\,\text{Pa}$, A and C at pressure $10^5\,\text{Pa}$, volume axis labeled V(L) with value 3 marked]
(1) $800$
(2) $1250$
(3) $1600$
(4) $1750$

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201-- Considering the positions of elements $A$, $_{1\Delta}M$, $_{r1}E$, and $_{r\Delta}X$ in the periodic table and their electronic configurations, which compound formed by any two of them is impossible?

$MX_\Delta$, $E_rA_r$ (1)	$EA$, $MX_r$ (2)
$EX_r$, $M_rA_\Delta$ (3)	$X_rA_r$, $EM$ (4)

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

• Every sublevel is identified by the quantum numbers $n$ and $l$.
• In filling sublevels, only the principal quantum number is relevant.
• From the relation $a = 4l + a$, the electronic capacity of sublevels ($a$) can be determined.
• In the atom $_{29}$Cu, the ratio of electrons with $l = 0$ to $l = 2$ is $0.7$.

1 (1)

2 (2)

3 (3)

4 (4)

203-- The outermost electronic configuration of the monoatomic ions $A^{r-}$, $D^{r+}$, and $E^{r+}$ ends in $3p^6$, $4p^6$, and $3d^5$ respectively. Which statement about them is correct?

1. Element E is in group 7 and element D is in group 13 of the periodic table.
2. The reactivity of elements E and D is greater than that of alkali metals in the same period.
3. The chemical properties of element A resemble those of its own period-18 group element.
4. The atomic number of one of the elements in the same group as element A, in the periodic table, is equal.

204-- Which of the following statements about the element just before Krypton ($_{36}$Kr) in the fourth period of the periodic table is correct?

• A) Element $_{37}$A is in the same group in the periodic table.
• B) Its atomic radius is larger than the atomic radius of element X.
• C) Its nonmetallic character is less than element M.
• D) Its physical state in the same period has a different physical state.
• E) The number of electrons with quantum number $l = 1$ equals its group number in the periodic table.

(1) A, T

(2) B, P

(3) A, B, T

(4) P, T, Th

205-- Metal A with halogen X forms the chemical compound $AX_r$. This compound reacts according to: $$2AX_r(s) + X_r(g) \xrightarrow{\Delta} 2AX_r(s)$$ Upon decomposition, $1.12$ g of $AX_r$ is completely decomposed and $0.72$ g of $AX$ is formed and $71.25$ mL of halogen gas $X_r$ is produced. The atomic mass of X is equal to the atomic mass of metal A. (Take the molar volume of gases at experimental conditions to be $28.5$ liters.)

(1) $1/15$

(2) $1/r\Delta$

(3) $1/\Delta$

(4) $1/V\Delta$

206-- How many of the following ionic compound formulas are correct?

• Magnesium nitride: $Mg_rN_r$ Gallium chloride: $GaCl_r$
• Copper(II) sulfide: $Cu_rS$ Cobalt(III) sulfate: $CO_r(SO_f)_r$
• Barium cyanide: $Ba(CN)_r$ Zinc phosphate: $Zn_r(PO_f)_r$

(1) 3

(2) 4

(3) 5

(4) 6

207-- Atoms present in a cube with side $4$ cm of manganese metal approximately have how many mole of valence electrons? (The mass of one cubic centimeter of manganese is $7.5$ g; $_{25}Mn = 55\ \text{g.mol}^{-1}$)

(1) $\Delta V/\Delta$

(2) $\varphi 1/1$

(3) $\varphi\Delta/\Lambda$

(4) $\varphi V/r$

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208 -- Which of the following statements is correct?

• [A)] In nonpolar molecular substances, as molar mass increases, intermolecular forces increase.
• [B)] Since the molar mass of $\mathrm{N_2}$ and $\mathrm{CO}$ are equal, $\mathrm{CO}$ has a boiling point closer to $\mathrm{N_2}$.
• [C)] Water and hydrogen sulfide; both molecules have polar bonds and boiling points close to each other.
• [D)] Since the molar mass of $\mathrm{F_2}$ is less than the molar mass of $\mathrm{HCl}$, the boiling point of $\mathrm{HCl}$ is higher than that of $\mathrm{F_2}$.

(1) A, B (2) A, T (3) B, P (4) B, T

209 -- A pure sample of $\mathrm{Na_2SO_4}$ has a molar mass of 88 and contains 10 and 15 percent by mass of water. Due to water absorption, the mass of the sample increases to 20 percent. The percent by mass of this salt under new conditions is how much, and if the initial sample mass is 35.5 grams, after complete reaction with barium chloride, how many grams of precipitate forms in water? (Read options from right to left; $\mathrm{BaCl_2(aq)}$ does not react with impurities; $O=16,\ Na=23,\ S=32,\ Ba=137\ \mathrm{g.mol^{-1}}$)
$$\mathrm{Na_2SO_4(aq) + BaCl_2(aq) \rightarrow 2NaCl(aq) + BaSO_4(s)}$$
(1) $51.26$ , $78.2$ (2) $51.26$ , $74.9$
(3) $85.22$ , $78.2$ (4) $85.22$ , $74.9$

210 -- According to the octet rule (Lewis structure), which of the following molecular structures is correct?

(A) $:\ddot{S}=C=\ddot{O}:$
(B) $:\ddot{O}=C\begin{array}{l} \ddot{C}l: \\ \ddot{C}l: \end{array}$
(P) $$S\begin{array}{cc} :O: & :O: \end{array}$$
(T) $$\begin{array}{c} :\ddot{O}: \\ \| \\ H-C-H \end{array}$$
(1) A, B (2) B, P (3) A, T (4) P, T

211 -- The ``solubility--temperature'' equation for salt A in water is: $S = 0.97\theta + 35$, where $S = 0.97\theta + 35$. If the molar solubility ratio of salt A at temperatures $0^\circ\mathrm{C}$ and $40^\circ\mathrm{C}$ is $2.46$, the ratio of the molar concentration of the saturated solution of B to the molar concentration of the saturated solution of A at $50^\circ\mathrm{C}$ is approximately equal to --- (molar masses of A and B are respectively 330 and 110 grams; ignoring the change in volume due to the effect of dissolving salt, the ``solubility--temperature'' equation for salt B in water is linear).
(1) $0.69$ (2) $1.03$ (3) $1.65$ (4) $2.51$

212 -- Which of the following statements about the alkane with the formula ``bond--line'' shown below is correct? ($H=1,\ C=12\ \mathrm{g.mol^{-1}}$)
[Figure: bond-line structure of a branched alkane]

• [A)] The name of the compound is 2-ethyl-7-methylnonane.
• [B)] Its molar mass is equal to 4.15 times the molar mass of propane.
• [C)] Its molecular formula is the same as 3-ethyldecane.
• [D)] The number of $\mathrm{CH_2}$ groups in the molecule is $1.5$ times the number of $\mathrm{CH_3}$ groups.

(1) A, T (2) P, T (3) A, B, P (4) B, P, T

213 -- 10 milliliters of sulfuric acid solution reacts completely with 210 milligrams of magnesium carbonate. The acid is completely consumed. How many grams and what molar concentration does 100 milliliters of that solution have?
$$\mathrm{MgCO_3(s) + H_2SO_4(aq) \rightarrow MgSO_4(aq) + CO_2(g) + H_2O(l)}$$
(Read options from right to left; $H=1,\ C=12,\ O=16,\ Mg=24,\ S=32\ \mathrm{g.mol^{-1}}$)
(1) $0.25$ , $2.45$ (2) $0.50$ , $2.45$ (3) $0.25$ , $4.9$ (4) $0.50$ , $4.9$

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214-- How many of the following statements are correct? $(H = 1,\ C = 12,\ Br = 80\ ;\ \text{g.mol}^{-1})$

• Natural gas is the building material of petrochemical industries.
• 0.25 mol of each alkene, with 40 grams of bromine, undergoes a complete reaction.
• In alkene molecules, each carbon atom has bonds to three other atoms.
• The molar mass of the second member of the alkane family is 0.75 times the molar mass of the second member of the alkyne family.

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

215-- The overall steps of a reaction are:
1) $2\text{NO}(\text{g}) \rightarrow \text{N}_2\text{O}_2(\text{g})$

216-- Referring to the partial periodic table below, how many of the related statements are correct?

Group $\rightarrow$	1	2	16	17
Period $\downarrow$
2		A	D
3	E			G
4		X		Z

• The metallic character of A is less than E.
• The electron affinity of G is greater than D.
• The atomic radius of X is larger than D and G.
• Among the identified elements, Z has the largest atomic radius.

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

217-- If 24.6 kJ of heat is given to 0.5 kg of ethanol and its temperature increases from $19^\circ\text{C}$ to $39^\circ\text{C}$, the specific heat capacity of ethanol is a few $\text{J.g}^{-1}.^\circ\text{C}^{-1}$. With the same amount of heat given to ethanol, how many grams of oxygen gas can be converted to ethanol under appropriate conditions? ($\Delta H$ of this conversion is $+295\ \text{kJ}$) $(O = 16\ \text{g.mol}^{-1})$
1) $8{,}500 \cdot 24.6$ 2) $8{,}500 \cdot 24.6$ 3) $2{,}750 \cdot 24.6$ 4) $2{,}750 \cdot 24.6$

218-- Regarding the two given reactions, how many statements are correct? (The chemical equations are balanced.)
$$\text{(I)}\ \text{C}_2\text{H}_5\text{OH}(\text{l}) + \text{O}_2(\text{g}) \rightarrow \text{CO}_2(\text{g}) + \text{H}_2\text{O}(\text{l})$$ $$\text{(II)}\ \text{Na}_2\text{CO}_3(\text{s}) + \text{HCl}(\text{aq}) \rightarrow \text{NaCl}(\text{aq}) + \text{CO}_2(\text{g}) + \text{H}_2\text{O}(\text{l})$$

• According to reaction I, burning one mole of ethanol produces 44.8 liters of gas at STP.
• In reaction II, if 7.5 mol of acid is used, 15 moles of water are produced, and the yield of reaction II is 90\%.
• Per gram of carbon-containing reactant, the molar ratio of $\text{CO}_2$ in reaction I to reaction II is $4/6$.
• In reaction II, if 100 grams of impure $\text{Na}_2\text{CO}_3$ is used, 1.5 mol of salt is formed, and the purity is 79.5\%.

$(H = 1,\ C = 12,\ O = 16,\ Na = 23\ :\ \text{g.mol}^{-1})$
1) 1 2) 2 3) 3 4) 4
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219 -- If 1 mol of $\mathrm{KClO_4}$ is heated in the presence of a catalyst in a 5-liter flask, at a constant rate of $0.1\ \mathrm{mol \cdot s^{-1}}$, according to the reaction: $2\mathrm{KCl(s)} + 3\mathrm{O_2(g)} \rightarrow 2\mathrm{KClO_3(s)}$, the reaction is decomposed; after a few seconds the reaction is complete and the graph of molar concentration changes of $\mathrm{O_2}$ versus time is shown. Which of the following is correct?

[Figure: Four graphs (1)--(4) showing concentration (mol$\cdot$L$^{-1}$) of $\mathrm{O_2}$ vs. $t$(s), with axes labeled up to 0.3 on y-axis and 5, 10, 15 on x-axis. Options (1) and (2) show linearly increasing then constant graphs reaching 0.15; options (3) and (4) show linearly increasing then constant graphs reaching 0.05.]

220 -- Which of the following statements is correct?

\={A}) The general formula of polyesters is $\left[\,\overset{\displaystyle O}{\overset{\displaystyle \|}{C}}-\overset{\displaystyle O}{\overset{\displaystyle \|}{C}}-O-R-O\right]_n$.
B) The number of lone pairs of electrons in the bonds of the Teflon monomer is 2.
P) Nails and skin of the body are made of natural polymers with functional groups containing atoms C, O, and N.
T) The average molar mass of polyethylene obtained from ethylene polymerization is independent of the amount of catalyst used.

(1) \={A}, B (2) \={A}, T (3) B, P (4) P, T

221 -- In how many cases below do the two compounds mix with each other?

[Figure: Four cases each showing two molecular structures: Case (1): cyclopentane with N substituent (pyrrolidine derivative) and $\mathrm{NH_2}$-terminated chain; and a dichloride compound $\mathrm{Cl_2}$ on a branched carbon. Case (2): $\mathrm{H_2N}$-chain with carbonyl and $\mathrm{OH}$ group ($\mathrm{HOOC}$, $\mathrm{NH_2}$); and a cyclopentane with a vinyl group. Case (3): shown structures. Case (4): shown structures.]

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

222 -- Referring to the graph below, which shows the logarithmic changes of molar concentration of reactant A in a reaction at a certain temperature, if the stoichiometric coefficient of A in the reaction equation is 2, and the ratio of the initial rate of reaction at 20 seconds to the average rate of consumption of A in the time interval 13 to 20 seconds is which of the following?

[Figure: Graph of $\log[\mathrm{A}]$ vs. $t$(s) showing a straight line decreasing from approximately 0.9 at $t=0$ to about 0.1 at $t=20$, with gridlines at $t = 5, 10, 15, 20$.]

(1) $0.374$ (2) $0.437$ (3) $0.785$ (4) $0.875$

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223 – Regarding a solution of hydrochloric acid (solution I) and a solution of hydrofluoric acid (solution II) with equal volume, temperature, and pH, how many of the following statements are correct?

• The number of initial moles of the two acids, for forming the two solutions, is not equal.
• The number of molecules in solution II is greater than the number of molecules in solution I.
• The number of anions produced from the ionization of the two acids and the electrical conductivity of the two solutions are equal.
• The total number of species present in solution I, compared to the total number of species present in solution II, is less.

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

224 – Regarding the hypothetical molecule with the structure below, which statement is correct?
[Figure: A molecule containing a benzene ring with an $\mathrm{HN}$ group and a side chain containing $\mathrm{N}$, $\mathrm{C=O}$, $\mathrm{OH}$, and $\mathrm{OH}$ groups]

1. The number of carbon atoms in it is $4.5$ times the number of oxygen atoms.
2. It has a functional group of hydroxyl and a repeating unit that forms a polyamide.
3. The number of single bonds between atoms in it is $5.4$ times the number of double bonds between them.
4. The number of hydrogen atoms is $1.25$ times the number of lone pairs of electrons on the atoms in it.