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WorksheetsREDOX REACTIONS Part-1 some basic concepts
Total questions: 45
Worksheet time: 45mins
1. Calculate number of neutrons present in 12 x 1025 atoms of oxygen (8O17) (Given: N A = 6 x 1023)
(a) 1800
(b) 1600
(c) 1800 N A
(d) 3200 N A
2. Calculate number of electrons present in 9.5 g
of PO3-4 :
(a) 6
(b)5NA
(c)0.1NA
(d) 4.7 N A
3.What is the charge of 96 amu of S2- ?
(a) 2 C
(b) 3.2 x 10 _19 C
(c) 9.6 x 10 -19 C
(d) 6 C
4. The total no. of neutrons present in 54 mL H2O (l) are:
(a) 3 Na
(b) 30 N A
(c) 24 NA
(d) none of these
5. The number of neutron in 5 g of D2O (D is 2 1H) are:
(a) 0.25 Na
(b) 2-5 NA
(c) 1 1. NA
(d) none of these
6. Aspirin has the formula C9H8O4. How many atoms of oxygen are there in a tablet weighing 360 mg?
(a) 1.204 xlO23
(b) 1.08 xlO22
(c) 1.204 xlO24
(d) 4.81 xlO21
7. A sample of ammonium phosphate, (NH4)3PO4, contains 6 moles of hydrogen atoms. The number of moles of oxygen atoms in the sample is:
(a) 1
(b) 2
(c) 4
(d) 6
8. 3.011 x 1022 atoms of an element weight 1.15 gm. The atomic mass of the element is:
(a) 10
(b) 2.3
(c) 35.5
(d) 23
9. Mass of one atom of the element?! is 3.9854 x 10-23 g. How many atoms are contained in 1 g of the element A?
(a) 2.509 xlO23
(b) 6.022 x 1023
(c) 12.044 x 1023
(d) None of these
10. Which has minimum number of atoms of oxygen ?
(a) 10 mL H2O (l)
(b) 0.1 mole of V2O5 (s)
(c) 12gmO3(g)
(d) 12.044 x 1022 molecules of CO2
11. The volume of a drop of water is 0.0018 mL then the number of water molecules present in two drop of water at room temperature is:
(a) 12.046 x 1019
(b) 1.084 x 1018
(c) 4.84 x 1017
(d) 6.023 x 1023
12. Common salt obtained from sea-water contains 8.775% NaCl by mass. The number of formula units of NaCl present in 25 g of this salt is :
(a) 3.367 x 1023 formula units
(b) 2.258 x 1022 formula units
(c) 3.176 x 10 23 formula units
(d) 4.73 x 1025 formula units
13. Caffiene has a molecular weight of 194. If it contains 28.9% by mass of nitrogen, number of atoms of
nitrogen in one molecule of caffeine is :
(a) 4
(b) 6
(c) 2
(d) 3
14. A 25.0 mm x 40.0 mm piece of gold foil is 0.25 mm thick. The density of gold is 19.32 g/cm3 How many gold atoms are in the sheet ? (Atomic weight : Au = 197.0)
(a) 7.7xl0 23
(b) 1.5x 1023
(c) 4.3x1021
(d) 1.47x1022
15. Density of dry air containing only N2 and O2 is 1.15 g/L at 740 mm and 300 K. What is % composition of N 2 by weight in the air ?
(a) 78%
(b) 85.5%
(c) 70.02%
(d) 62.75%
16. The vapour density of a mixture containing NO 2 andN2O4 is 27.6. The mole fraction of N2O4 in the mixture is:
(a) 0.1
(b) 0.2
(c) 0.5
(d) 0.8
17. Average atomic mass of magnesium is 24.31 a.m.u. This magnesium is composed of 79 mole % of 24 Mg and remaining 21 mole % of 25 Mg and 26 Mg. Calculate mole % of 26 Mg.
(a) 10
(b) 11
(c) 15
(d) 16
18. Calculate density of a gaseous mixture which consist of 3.01 x 10 24 molecules of N2 and 32 g of O2 gas at 3 atm pressure and 860 K temperature (Given : R = 1/12 atm L/mole.K)
(a) 0.6 g/L
(b) 1.2 g/L
(c) 0.3 g/L
(d) 12 g/L
19. If water sample are taken from sea, rivers or lake, they will be found to contain hydrogen and oxygen in the approximate ratio of 1 : 8. This indicates the law of:
(a) Multiple proportion
(b) Definite proportion
(c) Reciprocal proportions
(d) None of these
20. One of the following combinations illustrate law of reciprocal proportions :
(a) N2O3,N2O4,N2O5
(b) NaCl, NaBr, Nal
(c) CS2,CO2,SO2
(d) PH3,P2O3,P2O5
21. A sample of calcium carbonate (CaCO3) has the following percentage composition : Ca = 40%, C = 12%, O = 48%. If the law of constant proportions is true, then the weight of calcium in 4 g of a sample of calcium carbonate obtained from another source will be :
(a) 0.016 g
(b) 0.16 g
(c) 1.6 g
(d) 16 g
22. All the substances listed below are fertilizers that contribute nitrogen to the soil. Which of these is the richest source of nitrogen on a mass percentage basis ?
(a) Urea, (NH2)2CO
(b) Ammonium nitrate, NH4NO3
(c) Nitric oxide, NO
(d) Ammonia, NH3
23. A given sample of pure compound contains 9.81 gm of Zn, 1.8 x 1023 atoms of chromium and 0.60 mole of oxygen atoms. What is the simplest formula ?
(a) ZnCr2O7
(b) ZnCr2O4
(c) ZnCrO4
(d) ZnCrO6
24. What is the empirical formula of vanadium oxide, if 2.74 g of the metal oxide contains 1.53 g of metal ?
(a) V2O3
(b) VO
(c) V2O5
(d) V2O7,
25. The hydrated salt Na2CO3.xH2O undergoes 63% loss in mass on heating and becomes anhydrous. The value of x is:
(a) 10
(b) 12
(c) 8
(d) 18
26. What percentage of oxygen is present in the compound CaCO3-3Ca3(PO4)2 ?
(a) 23.3%
(b) 45.36%
(c) 41.94%
(d) 17.08%
27. A gaseous compound is composed of 85.7% by mass carbon and 14.3% by mass hydrogen. It’s density is 2.28 g/litre at 300 K and 1.0 atm pressure. Determine the molecular formula of the compound :
(a) C2H2
(b) C2H4
(c) C4H8
(d) C4H10
28. The sulphate of a metal M contains 9.87% of M. This sulphate is isomorphous with ZnSO 4 • 7H 2O. The atomic weight of M is :
(a) 40.3
(b) 36.3
(c) 24.3
(d) 11.3
29. On analysis, a certain compound was found to contain 254 g of iodine (at. mass 127) and 80 g oxygen (at. mass 16). What is the formula of the compound ?
(a) IO
(b)I2O
(c) I5O3
(d)I2O5
30. A compound used in making nylon, is 43.8% oxygen. There are four oxygen atoms per molecule. What is the molecular weight of compound?
(a) 36
(b) 116
(c) 292
(d) 146
31. 44 g of a sample on complete combustion gives 88 gmCO2 and 36 gm ofH2O.The molecular formula of the compound may be:
(a) C4H6
(b) C2H6O
(c) C2H4O
(d) C3H6O
32. Two element X (at. mass = 75) and Y (at. mass = 16) combine to give a compound having 75.8% of X. The formula of the compound is:
(a) XY
(b) X2Y
(c) X2Y2
(d) X2Y3
33. Manganese forms non-stoichiometric oxides having the general formula MnO x. The value of x for the compound that analyzed 64% by mass Mn:
(a) 1.16
(b) 1.83
(c) 2
(d) 1.93
34. Which statement is false for the balanced equation given below ?
CS 2 + 30 2→2SO 2 + CO 2
(a) One mole of CS2 will produce one mole of C02
(b) The reaction of 16 g of oxygen produces 7.33 g of CO2
(c) The reaction of one mole of O 2 will produce 2/3 mole of
SO 2
(d) Six molecules of oxygen requires three molecules of CS2
35. 2.0 g sample contain mixture of SiO2 and Fe2O3, on very strong heating leave a residue weighing 1.96 g.
The reaction responsible for loss of weight is
Fe2O3 (s)-------- > Fe3O4(s) + O2(g), (unbalance equation) What is the percentage by mass of SiO 2 in original sample ?
(a) 10%
(b) 20%
(c) 40%
(d) 60%
36. How many moles of P4 can be produced by reaction of 0.10 moles Cas(PO4)3F, 0.36 mole SiO 2 and 0.90 moles C according to the following reaction ?
4 Ca5(PO4)3F + 18 SiO2 + 30 C ------ > 3P4 + 2CaF2 + 18CaSiO3 + 30 CO
(a) 0.060
(b) 0.030
(c) 0.045
(d) 0.075
37. The mass of N2F4 produced by the reaction of 2.0 g of NH3 and 8.0 g of F2 is 3.56 g. What is the per cent yield?
2NH3 + 5F2---- > N2F4+6HF
(a) 79.0
(b) 71.2
(c) 84.6
(d) None of these
38. 9 moles of “D” and 14 moles of E are allowed to react in a closed vessel according to give: reactions.
Calculate number of moles of B formed in the end of reaction, if 4 moles of G an present in reaction vessel.
(Percentage yield of reaction is mentioned in the reaction)
Step-1 3D + 4E 80% 5C + A
Step-2 3C + 5G 50%6B +F
(a) 2.4
(b) 30
(c) 4.8
(d) 1
39. 100 ml. of H2SO4 solution having molarity 1 M and density 1.5 g/mL is mixed with 400 mL of water.
Calculate final molarity of H2SO4 solution, if final density is 1.25 g/mL :
(a) 4.4 M
(b) 0.145 M
(c) 0.52 M
(d) 0.227 M
40. An ideal gaseous mixture of ethane (C 2H 6) and ethene (C 2H 4) occupies 28 litre at I atm and 273 K. The mixture reacts completely with 128 g O 2 to produce CO 2 and H 2O. Mole fraction at C2H6 in the mixture is:
(a) 0.6
(b) 0.4
(c) 0.5 ,
(d) 0.8
41. The density of a 56.0% by weight aqueous solution of 1-propanol (CH 3CH2CH2OH) is 0.8975
g/em 3. What is the mole fraction of the compound ?
(a)0.292
(b) 0.227
(c) 0.241
(d) 0.276
42. An aqueous solution of ethanol has density 1.025 g/mL and it is 2 M. What is the molality of this-solution ?
(a) 1.79
(b) 2.143
(c) 1.951
(d) None of these
43. Calculate the mass of anhydrous HC1 in 10 mL of concentrated HC1 (density = 1.2 g / mL) solution having 37% HC1 by weight.
(a) 4.44 g
(b) 4.44 mg
(c) 4.44 x 10-3 mg
(d) 0.444 ng
44. Fluoxymesterone, C20H29F03, is an anabolic steroid. A 500 mL solution is prepared by dissolving 10.0 mg of the steroid in water, 1.0 mL portion of this solution is diluted to a final volume of 1.00 L. What is the resulting molarity ?
(a) 1.19x10 -10
(b) 1.19 xlO-7
(c) 5.95x10 - 8
(d) 2.38 x 10-11
45. A sample of sodium has a mass of 46 g. What is the mass of the same number of calcium atoms as sodium atoms present in given sample ?
(a) 46 g
(b) 20 g
(c) 40 g
(d) 80 g
