#### Basic Concepts of Chemistry and Chemical Calculations Book Back Questions

11th Standard

Reg.No. :
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Chemistry

Time : 00:45:00 Hrs
Total Marks : 30
5 x 1 = 5
1. The mass of a gas that occupies a volume of 612.5 ml at room temperature and pressure (250 c and 1 atm pressure) is 1.1g. The molar mass of the gas is

(a)

66.25 g mol-1

(b)

44 g mol-1

(c)

24.5 g mol-1

(d)

662.5 g mol-1

2. Which of the following compound(s) has /have a percentage of carbon same as that in ethylene (C2H4)

(a)

propene

(b)

ethyne

(c)

benzene

(d)

ethane

3. Which of the following is/are true with respect to carbon -12

(a)

relative atomic mass is 12 u

(b)

the oxidation number of carbon is +4 in all its compounds.

(c)

1 mole ofcarbon-12 contain 6.022 x 1022 carbon atoms.

(d)

All of these

4. Which one of the following is used as a standard for atomic mass.

(a)

6C12

(b)

7C12

(c)

6C13

(d)

6C14

5. The equivalent mass of potassium permanganate in alkaline medium is:
MnO4- + 2H2O + 3e-$\rightarrow$ MnO2 + 4OH-

(a)

31.6

(b)

52.7

(c)

79

(d)

None of these

6. 3 x 2 = 6
7. What do you understand by the term oxidation number?

8. Distinguish between oxidation and reduction.

9. The density of carbon dioxide is equal to 1.965 kgm-3 at 273 K and 1 atm pressure. calculate the molar mass of CO2

10. 3 x 3 = 9
11. Mass of one atom of an element is 6.645 x 10-23g. How many moles of element are there in 0.320 kg.

12. What is the difference between molecular mass and molar mass? Calculate the molecular mass and molar mass for carbon monoxide.

13. How many moles of ethane is required to produce 44 g of CO2(g) after combustion

14. 2 x 5 = 10
15. The reaction between aluminum and ferric oxide can generate temperatures up to 3273 K and is used in welding metals. (Atomic mass of AC = 27 u atomic mass of O = 16 u )
2Al + Fe2O3 $\longrightarrow$ Al2O3 + 2Fe;  If in this process, 324 g of aluminum is allowed to react with 1.12 kg of ferric oxide
i) Calculate the mass of Al2O3 formed
ii) How much of the excess reagent is left at the end of the reaction?

16. Balance the following equations by oxidation number method
i) ${ K }_{ 2 }{ Cr }_{ 2 }{ O }_{ 7 }+KI+{ H }_{ 2 }SO_{ 4 }\longrightarrow { K }_{ 2 }{ SO }_{ 4 }+{ Cr }_{ 2 }({ SO }_{ 4 })+{ I }_{ 2 }+{ H }_{ 2 }O$
ii) ${ K }Mno_{ 4 }+{ Na }_{ 2 }{ So }_{ 3 }\longrightarrow { MnO }_{ 2 }+{ Na }_{ 2 }{ So }_{ 4 }+KOH$
iii) $Cu+{ HNO }_{ 3 }\longrightarrow Cu\left( { No }_{ 3 } \right) _{ 2 }+{ No }_{ 2 }+{ H }_{ 2 }O$
iv) ${ KMn }O_{ 4 }+{ H }_{ 2 }{ C }_{ 2 }{ O }_{ 4 }+{ H }_{ 2 }{ SO }_{ 4 }\longrightarrow { K }_{ 2 }{ SO }_{ 4 }+{ MnSO }_{ 4 }+{ CO }_{ 2 }+{ H }_{ 2 }O$