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Chemistry · Some Basic Concepts of Chemistry
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Chemistry · Some Basic Concepts of Chemistry
What defines a limiting reagent in a chemical reaction?
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According to the convention for rounding off numbers, if the rightmost digit to be removed is \( 5 \), followed by no other digits, which of the following pairs are correctly rounded off to two significant figures?
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Which of the following physical quantities is an SI base quantity, along with its correct standard SI unit symbol?
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Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).\n Assertion (A): Dalton's atomic theory could successfully explain the law of conservation of mass and law of multiple proportions.\n Reason (R): Dalton proposed that matter consists of indivisible atoms and atoms of a given element have identical properties. \nIn the light of the above statements, choose the correct answer from the options given below:
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What is the mass per cent of oxygen in sodium sulphate (\( \text{Na}_2\text{SO}_4 \))? (Atomic masses: \( \text{Na} = 23, \text{S} = 32, \text{O} = 16 \))
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Which of the following mixtures represents a homogeneous mixture?
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If the density of methanol is \( 0.793\text{ kg L}^{-1} \), what is its volume needed for making \( 2.5\text{ L} \) of its \( 0.25\text{ M} \) solution? (Molar mass = \( 32\text{ g mol}^{-1} \))
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How many moles of carbon dioxide (\( \text{CO}_2 \)) are required to be produced from the combustion of methane to obtain \( 22\text{ g} \) of \( \text{CO}_2 \)?
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In the macroscopic particle arrangement depicted below, what represents the primary driving factor for the phase transition from state (a) to state (b) and subsequently to state (c)?
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How many significant figures are present in the number \( 0.0025 \)?
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Hydrogen combines with oxygen to form two compounds, namely water and hydrogen peroxide. The masses of oxygen which combine with a fixed mass of hydrogen (\( 2 \text{ g} \)) are \( 16 \text{ g} \) and \( 32 \text{ g} \), respectively. This ratio (\( 16:32 = 1:2 \)) is an illustration of which law?
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Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In the multiplication of \( 2.5 \) and \( 1.25 \), the final reported result is \( 3.1 \) rather than \( 3.125 \). Reason (R): In multiplication or division, the final result must not have more significant figures than the measurement with the fewest significant figures. In the light of the above statements, choose the correct answer from the options given below:
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How much copper can be obtained from \( 100\text{ g} \) of copper sulphate (\( \text{CuSO}_4 \))? (Atomic masses: \( \text{Cu} = 63.5, \text{S} = 32, \text{O} = 16 \))
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Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).\n Assertion (A): The formula mass of sodium chloride is taken as 58.5 u instead of molecular mass.\n Reason (R): Solid sodium chloride does not exist as a single discrete molecule; rather, ions are arranged in a three-dimensional lattice structure. \nIn the light of the above statements, choose the correct answer from the options given below:
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Which of the following prefix symbols correctly represents the multiplier \( 10^{-15} \) in the SI system?
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What is the mass percentage of carbon in ethanol (\( \text{C}_2\text{H}_5\text{OH} \))? (Atomic masses: \( \text{C} = 12.011\text{ u} \), \( \text{H} = 1.008\text{ u} \), \( \text{O} = 16.00\text{ u} \))
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Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): During any physical change or chemical reaction in a closed system, the total mass of the system increases progressively. Reason (R): Matter can neither be created nor destroyed in chemical reactions, which forms the basis of the Law of Conservation of Mass. In the light of the above statements, choose the correct answer from the options given below:
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Boron occurs in nature as two isotopes: \( ^{10}\text{B} \) (isotopic mass = \( 10.01\text{ u} \)) and \( ^{11}\text{B} \) (isotopic mass = \( 11.01\text{ u} \)). If the average atomic mass of boron is \( 10.81\text{ u} \), the percentage relative abundance of the lighter isotope \( ^{10}\text{B} \) is:
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Given below are two statements: Statement I: Significant figures are meaningful digits in a measured quantity that include all certain digits plus one uncertain digit. Statement II: Leading zeros in a number are always considered significant. In the light of the above statements, choose the most appropriate answer from the options given below:
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A sample of gas occupies a volume of \( 4.5\text{ dm}^3 \). What is this volume expressed in the SI unit of volume (\( \text{m}^3 \))?
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In the SI system, which of the following lists represents ONLY base physical quantities?
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Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Avogadro's law states that equal volumes of all gases under the same conditions of temperature and pressure contain equal number of molecules. Reason (R): Volume of a gas is directly proportional to the number of moles at constant temperature and pressure. In the light of the above statements, choose the correct answer from the options given below:
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