In a reaction: \(SnO_{2} + 2C → Sn + 2CO\) the mass of coke containing 80% carbon required to reduce 0.302 kg of pure tin oxide is?
(Sn - 119, O - 16, C - 12).
คำตอบ
(C)
0.06 kg
3
Cr2O7 + 6Fe2+ + 14H+ → 2Cr3+ +6Fe3+ + 7H2O. In the above , the oxidation number of chromium changed from?
คำตอบ
(A)
+7 to +3
4
In the reaction 1O-3 + 5l- + 6H+ → 312 + 3H2O, the oxidizing agent is?
คำตอบ
(C)
1O-
5
Fe\(_2\)O\(_{3(s)}\) + 2Al\(_{(s)}\) → Al\(_2\)O\(_3\) + 2Fe\(_{(s)}\). If the heats of formation of Al\(_2\)O\(_3\) and Fe\(_2\)O\(_3\) are - 1670 kJmol\(^{-1}\) and - 822 kJmol\(^{-1}\) respectively, the enthalpy change in kJ for the reaction is ?
คำตอบ
(C)
-848
6
Iron galvanized with zinc is cathodically protected from corrosion. This is because?
คำตอบ
(A)
zinc has a more positive oxidation potential than iron
7
Which of the following samples will react fastest with dilute trioxonitrate (V) acid?
คำตอบ
(D)
5 g of powered CaCO3 AT 50°C
8
In the reaction:
2Hl(g) ↔ H2(g) + l2(g)' ΔH = 10 kj;
The concentration of iodine in the equilibrium mixture can be increased by?
คำตอบ
(B)
raising the temperature
9
Which of the following gases can be collected by the upward displacement of air?
คำตอบ
(D)
Cl 2
10
The brown fumes given off when trioxonitrate (V) acid is heated consist of ?
คำตอบ
(A)
NO2 and O2
11
Which of the following tests will completely identify anyone of surphur (VI) oxide, hydrogen, carbon (IV) oxide and nitrogen (II) oxide?
คำตอบ
(B)
Pass each gas into lime water
12
In the Haber process for the manufacture of ammonia, the catalyst commonly used is finely divided ?
คำตอบ
(C)
iron
13
A metallic oxide which reacts with both HCl and NaOH to give salt and water only can be classified as?
คำตอบ
(D)
an amphoteric oxide
14
Which of the following metals will liberate hydrogen from steam or dilute acid?
คำตอบ
(B)
Iron
15
Coal fire should not be used in poorly ventilated rooms because ?
คำตอบ
(C)
of the acumulation of CO which causes suffocation
16
The major component of the slag from the production of iron is?
คำตอบ
(D)
calcium trioxosilicate (IV)
17
Sodium hydroxide should be stored in properly closed containers because it?
คำตอบ
(A)
readily asborbs water vapour to air
18
To make coloured glasses, small quantities of oxides of metals which form coloured silicates are often added to the reaction mixture consisting of Na2CO3 and SiO2. Such a metals is a?.
คำตอบ
(D)
copper
19
Which of the following compounds gives a yellow residue when heated and also reacts with aqueous sodium hydroxide to give a white gelatinous precipitate soluble in excess sodium hydroxide solution?
คำตอบ
(B)
ZnCO3
20
A cycloalkane with the molecular formula C5H10 has ?
คำตอบ
(C)
three isomers
21
The label on a reagent bottle containing a clear organic liquid dropped off.The liquid was neutral to litmus and gave a colourless gas with metallic sodium. The liquid must be an?
คำตอบ
(C)
alkanol
22
Alkaonic acids have low volatility compared with alkanols because they?
คำตอบ
(D)
form two hydrogen bonds while alkanols form one
23
The octane number of a fuel whose performance is the same as that of a mixture of 55 g of 2,2,4- trimethly pentane and 45 g of n-heptane is ?
คำตอบ
(B)
55
24
Which of the following is formed when maltose reacts with concentrated tetraoxosulphate (VI) acid ?
คำตอบ
(C)
Charcoal
25
If a gas occupies a container of volume 146 cm3 at 18°C and 0.971 atm, its volume in cm3 at s.t.p is?
คำตอบ
(A)
133
26
The volume occupies by 1.58g of a gas at s.t.p is 500cm3. What is the relative molecular mass of the gas?
(G.M.V at s.t.p = 22.40dm3)
คำตอบ
(D)
71
27
Equal volumes of CO,SO2, NO2 and H2S were released into a room at the same point and time. Which of the following gives the order of diffusion of the gases to the opposite corner of the room?
(S = 32, C = 12, O = 16, N = 14, H = 1)
คำตอบ
(D)
CO,H2S,NO2,SO2
28
A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that?
Which of the four atoms P,q,R and in S in the above data can be described by the following properties relative atomic mass is greater than 30 but less than 40; it has an odd atomic number and forms a unipositive ion in solution?
คำตอบ
(D)
S
30
Which of the following terms indicates the number of bonds that can be formed by an atom?
คำตอบ
(B)
Valence
31
X(g) → X\(^-\)(g). The type of energy involved in the above transformation is?
คำตอบ
(D)
electron affinity
32
Chlorine, consisting of two isotopes of mass numbers 35 and 37, has an atomic mass of 35.5.
The relative abundance of the isotope of mass number 37 is?
คำตอบ
(B)
25
33
10.0 dm3 of air containing H2S as an impurity was passed through a solution of Pb(NO3)2 until all the H2S had reacted. The precipitate of PbS was found to weigh 5.02 g. According to the equation:
Pb(NO3)2 + H2S → PbS + 2HNO3 the percentage by volume of hydrogen sulphide in the air is?
(Pb = 207, S = 32, GMV at s.t.p = 22.4dm3)
คำตอบ
(C)
4.70
34
A blue solid, T, which weighed 5.0g was placed on a table. After 8 hours, the resulting pink solid was found to weigh 5.5g. It can be inferred that substance T?
คำตอบ
(B)
is hygroscopic
35
The solubility in moles per dm3 of 20g of CuSO4 dissolve in 100 of water at 180°C is?
(Cu = 63.5, S = 32, O = 16)
คำตอบ
(C)
1.25
36
Smoke consist of?
คำตอบ
(B)
solid or liquid particles dispersed in gas
37
Na2C2O4 + CaCl2 → CaC2O4 + 2NaCl. Given a solution of 1.9g of sodium oxalate in 50g of water at room temperature, calculate the minimum volume of 0.1 M calcium oxalate using the above equation?
คำตอบ
(A)
1.40 χ 102 dm3
38
2.0g of a monobasic acid was made up to 250 cm3 with distilled water. 25.00 cm3 of this solution required 20.00cm3 of 0.1 M NaOH solution for complete neutralization. The molar mass of the acid is?
คำตอบ
(C)
100 g
39
What is the concentration of H+ ions in moles per dm3 of a sodium of pH 4.398?
คำตอบ
(A)
4.0 χ 10-5
40
What volume of 11.0 M hydrochloric acid must be dilute to obtain 1 dm3 of 0.05 M acid?
คำตอบ
(A)
0.05 dm3
41
If 10.8 g of silver is deposited in a silver coulometer volume of oxygen liberated is?
คำตอบ
(A)
0.56 dm3
42
0.1 faraday of electricity deposited 2.95 g of nickel during electrolysis of an aqueous solution.
Calculate the number of moles of nickel that will be deposited by 0.4 faraday?
(Ni = 58.7)
คำตอบ
(A)
0.20
43
Changes in the physical in the scheme above.The letter X,Y and Z respectively represent
คำตอบ
(A)
sublimation, condensation and freezing
44
Use the graph above to answer this question. The structure of cis-2-butene is
