Which of the following statement indicates that the law of multiple proportions is being followed?
1. | A sample of carbon dioxide taken from any source will always have carbon and oxygen in the ratio of 1:2. |
2. | Carbon forms two oxides namely, CO2 and CO, where masses of oxygen that combine with a fixed mass of carbon are in the simple ratio of 2:1. |
3. | When magnesium burns in oxygen, the amount of magnesium used for the reaction is equal to the amount of magnesium formed in magnesium oxide. |
4. | At constant temperature and pressure, 200 mL of hydrogen will combine with 100 mL of oxygen to produce 200 mL of water vapour. |
Match the following:
COLUMN I | COLUMN II |
A. 88 g of CO2 | 1. 0.25 mol |
B. 6.022×1023 molecules of H2O | 2. 2 mol |
C. 5.6 L of O2 at STP | 3. 3 mol |
D. 96 g of O2 | 4. 1 mol |
A | B | C | D | |
1. | 2 | 4 | 1 | 3 |
2. | 1 | 2 | 3 | 4 |
3. | 1 | 4 | 3 | 2 |
4. | 4 | 1 | 3 | 2 |
Match the following physical quantities with units.
Physical quantity | Unit |
A. Molarity | 1. mol kg-1 |
B. Molality | 2. mol L-1 |
C. Pressure | 3. Candela |
D. Luminous intensity | 4. Pascal |
Codes
A | B | C | D | |
1. | 1 | 4 | 2 | 3 |
2. | 2 | 1 | 4 | 3 |
3. | 1 | 4 | 3 | 2 |
4. | 4 | 1 | 3 | 2 |
Assertion (A): | The empirical mass of ethene is half of its molecular mass. |
Reason (R): | The empirical formula represents the simplest whole-number ratio of the various atoms present in a compound. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
Given below are two statements:
Assertion (A): | One atomic mass unit is defined as one-twelfth of the mass of one carbon-12 atom. |
Reason (R): | The carbon-12 isotope is the most abundant isotope of carbon and has been chosen as the standard. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Assertion (A): | The significant figure for 0.200 is 3, whereas the significant figure for 200 is 1. |
Reason (R): | Zero at the end or right of a number is significant, provided it is not on the right side of the decimal point. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Assertion (A): | The combustion of 16 g of methane gives 18 g of water. |
Reason (R): | In the combustion of methane, water is one of the products. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
Identify the reaction that does not obey the law of conservation of mass from the provided options.
1.
2.
3.
4.
The incorrect statement among the following is:
1. | A molecule of a compound has atoms of different elements. |
2. | A compound cannot be separated into its constituent elements by the physical method of separation. |
3. | A compound retains the physical properties of its constituent elements. |
4. | The ratio of atoms of different elements in a compound is fixed. |
If the density of the solution is 3.12 g ml-1, then what will be the mass of the 1.5 ml solution in two significant figures?
1. | \(4.4~\mathrm{g}\) | 2. | \(4680 \times 10^{3} ~\mathrm{g}\) |
3. | \(4.7~\mathrm{g}\) | 4. | \(46.80~\mathrm{g}\) |