Q. No.The number of significant figures in the numbers 5005, 500.0, and 126,000 are, respectively:
1. 2, 4, and 3
2. 4, 1, and 3
3. 4, 4, and 6
4. 4, 4, and 3
What is the difference between 0.50 mol Na₂CO₃ and 0.50 M Na₂CO₃?
| 1. | They represent different amounts of Na₂CO₃. |
| 2. | 0.50 mol represents the amount of Na₂CO₃, whereas 0.50 M represents its molarity. |
| 3. | 0.50 mol Na₂CO₃ produces more ions. |
| 4. | None of the above. |
Round up the following numbers into three significant figures:
(i) 10.4107
(ii) 0.04597
| 1. | 10.4, 0.0460 | 2. | 10.41, 0.046 |
| 3. | 10.0, 0.04 | 4. | 10.4, 0.0467 |
The following data was obtained when dinitrogen and dioxygen react together to form different compounds:
| Mass of dinitrogen | Mass of dioxygen | |
| i. | 14 g | 16 g |
| ii. | 14 g | 32 g |
| iii. | 28 g | 32 g |
| iv. | 28 g | 80 g |
The law of chemical combination applicable to the above experimental data is:
1. Law of reciprocal proportions
2. Law of multiple proportions
3. Law of constant composition
4. None of the above.
The numbers 234,000 and 6.0012 can be represented in scientific notation as:
| 1. | \(2.34 \times 10^{-9} \text { and } 6 \times 10^3\) |
| 2. | \(0.234 \times 10^{-6} \text { and } 60012 \times 10^{-9}\) |
| 3. | \(2.34 \times 10^{-9} \text { and } 6.0012 \times 10^{-9}\) |
| 4. | \(2.34 \times 10^5 \text { and } 6.0012 \times 10^0\) |
| List-I | List-II | ||
| a. | Micro | i. | m |
| b. | Mega | ii. | m |
| c. | Giga | iii. | m |
| d. | Femto | iv. | m |
| a | b | c | d | |
| 1. | i | iv | iii | ii |
| 2. | iii | iv | ii | i |
| 3. | ii | iii | iv | i |
| 4. | i | iii | iv | ii |
How many grams of HCl are required to react with 5.0 g of manganese dioxide in the reaction provided?
\(4 \mathrm{HCl}_{(\mathrm{aq})}+\mathrm{MnO}_{2(\mathrm{~s})} \rightarrow 2 \mathrm{H}_2 \mathrm{O}_{(\mathrm{l})}+\mathrm{MnCl}_{2(\mathrm{aq})}+\mathrm{Cl}_{2(\mathrm{~g})}\)
1. 4.8 g
2. 6.4 g
3. 2.8 g
4. 8.4 g
Find the mass of CaCO₃ required to completely react with 25 mL of 0.75 M HCl according to the reaction:
CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + CO₂(g) + H₂O(l)
1. 0.36 g
2. 0.09 g
3. 0.96 g
4. 0.66 g
The molar mass of naturally occurring Argon isotopes is:
| Isotope | Isotopic molar mass | Abundance |
| 36-Ar | 35.96755 g mol–1 | 0.337% |
| 38-Ar | 37.96272 g mol–1 | 0.063% |
| 40-Ar | 39.9624 g mol–1 | 99.600% |
| 1. | 49.99947 g mol-1 | 2. | 39.99947 g mol-1 |
| 3. | 35.59947 g mol-1 | 4. | 45.59947 g mol-1 |
Determine the number of significant figures that should be present in the final answers for each of the following expressions:
| I. | 0.02856 × 298.15 × 0.112 / 5785 |
| II. | 5 × 5.364 |
| III. | 0.0125 + 0.7864 + 0.0215 |
| 1. | 4, 4, 3 | 2. | 3, 3, 4 |
| 3. | 4, 3, 4 | 4. | 3, 4, 4 |
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