If the mass of air per unit area at sea level is 1034 g cm–2, pressure in pascal will be:
1. 1.01332 × 105 Pa
2. 1.01332 × 106 Pa
3. 1.01332 × 107 Pa
4. 1.01332 × 108 Pa
The SI unit of mass is:
1. Kilogram (kg)
2. Gram (g)
3. Pascal (Pa)
4. Kilometres (km)
A significant figure is defined as :
| 1. | The total number of digits in a number, including the last digit that represents the uncertainty of the result. |
| 2. | The total number of digits in a number, excluding the last digit, which represents the uncertainty of the result. |
| 3. | The total number of digits in a number including the last digit that represents the certainty of the result. |
| 4. | The total number of last digits that represents the uncertainty of the result. |
The chloroform contamination level in water is 15 ppm (by mass of chloroform). Calculate the molality of chloroform in this water sample, which represents the number of moles of chloroform dissolved per kilogram of pure water solvent:
1. 3.25 × 10-4
2. 1.5 × 10-3
3. 7.5 × 10-3
4. 1.25 × 10-4
If the speed of light is 3.0 × 108 m s–1, then the distance covered by light in 2.00 nanoseconds will be -
1. 0.500 m
2. 0.600 m
3. 0.700 m
4. 0.800 m
In a reaction A + B2 → AB2,
A will act as a limiting reagent if :
| i. | 300 atoms of A reacts with 200 molecules of B |
| ii. | 2 moles A reacts with 3 moles B2 |
| iii. | 100 atoms of A reacts with 100 molecules of B |
| iv. | 5 moles A reacts with 2.5 moles B |
| v. | 2.5 moles A reacts with 5 moles B2 |
Choose the correct option:
| 1. | (i), (ii) | 2. | (i), (ii), (v) |
| 3. | (ii), (v) | 4. | All |
If 10 volumes of H2 gas react with 5 volumes of O2 gas, the volumes of water vapor produced would be:
1. 9
2. 8
3. 10
4. 11
15.15 pm in the basic unit will be
1. 1.515 × 10–12 m
2. 2.57 × 10–11 m
3. 2.87 × 10–11 m
4. 1.515 × 10–11 m
Which will have the largest number of atoms among the following?
| 1. | 1 g Au (s)
|
2. | 1 g Na (s)
|
| 3. | 1 g Li (s)
|
4. | 1 g of Cl2(g) |
What would be the molarity of a solution of ethanol in water if the mole fraction of ethanol is 0.040?
(assume the density of water to be 1)
1. 3.143 M
2. 2.314 M
3. 2.413 M
4. 2.141 M