Unlock Chemistry Success Basic Concepts and Calculations one mark for 11 th Standard

Basic Concepts and Calculations Choose the best answer:

1. 40 ml of methane is completely burnt using 80 ml of oxygen at room temperature the volume of gas left after cooling to room temperature is

a. 40 ml CO2 gas

b. 40 ml CO2 gas and 80 ml H2O gas

c. 60 ml CO2 gas and 60 ml H2O gas

d. 120 ml CO2 gas

Ans: (a)

2. Carbon forms two oxides, namely carbon monoxide and carbon dioxide. The equivalent mass of which element remains constant?

a. Carbon

b. Oxygen

C. Both carbon and oxygen

d. neither carbon nor oxygen

Ans: (b)

3. The equivalent mass of a trivalent metal element is 9g eq-1 the molar mass of its anhydrous oxide is

a. 102g

b. 27g

c. 270g

d. 78g

Ans: (a)

4. 1 g of an impure sample of magnesium carbonate (containing no thermally decomposable impurities) on complete thermal decomposition gave 0.44g of carbon dioxide gas. The percentage of impurity in the sample is

a. 0%

b. 4.4%

c. 16%

d. 8.4%

5. When 6.3g of sodium bicarbonate is added to 30g of acetic acid solution, the residual solution is found to weigh 33g. The number of moles of carbon dioxide released in the reaction is

a. 3

b. 0.75

c. 0.075

d. 0.3

Ans: (c)

6. Two 22.4 liter containers A and B contains 8g of O2 and 8g of SO2 respectively at 273K and 1 atom pressure, then a

a. Number of molecules in A and B are same

b. Number of molecules in B is more than that in A

c. The ratio between the number of molecules in A to number of molecules in B is 2:1

d. Number of molecules in B is three times greater than the number of molecules in A.

Ans: (c)

7. What is the mass of precipitate formed when 50 ml of 8.5% solution of AgNO3 is mixed with 100 ml of 1.865% potassium chloride solution?

a. 3.59g

b. 7g

c. 14g

d. 28g

Ans: (a)

8. Which of the following contain same number of carbon atoms as in 6g of carbon-12

a. 7.5g ethane

b. 8g methane

c. both (a) and (b)

d. none of these

Ans: (c)

9. Which of the following compounds has/have percentage of carbon same as that in ethylene (C2H4)

a. propene

b. ethyne

c. benzene

d. ethane

Ans: (a)

10. What is the mass of precipitate formed when 50 ml of 8.5% solution of AgNO3 is mixed with 100 ml of 1.865% potassium chloride solution?

a. 3.59g

b. 7g

c. 14g

d. 28g

Ans: (a)

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