Mole concept

Mole concept is a Science & Technology concept from the MPSC syllabus, tested in 5 past MPSC questions across 4 exam years between 2015 and 2022. Below are those real questions with their correct answers and explanations, plus the concepts worth being comfortable with first.

Real questions

Years tested

4 · 2015–2022

In context

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Asked in

2022 2021 2019 2015

What you need to know first

Atomic mass unitBasic ChemistryDefinition of moleAtomic weightsBasic chemistry formulasAtomic mass calculationBasic stoichiometryAtomic mass units

What mastering this unlocks

Ideal gas lawGas equationsScientific UnitsAtomic mass unitDensity

Real questions that test this

'1 मोल' ही किंमत पुढील कोणत्या किमतीशी समप्रमाणात आहे ? / 1 mole is equal to which quantity from the following?

(a)12 ग्रॅम वजनातील C-12 चे अणू / 12 grams of C-12 atoms

(b)6.022137 × 10²³ अणू (कोणत्याही पदार्थाचे) / 6.022137 × 10²³ atoms (of any material)

(d)1 cm³ आकारमानात बसणारे कोणत्याही पदार्थाचे एकूण अणू / atoms of any material in a volume of 1 cm³

1)अ आणि ब / a and b✓ Correct

2)ब आणि क / b and c

3)क आणि ड / c and d

4)ड आणि अ / d and a

One mole of a substance contains Avogadro's number of particles (6.022 × 10²³) and has a mass equal to its atomic/molecular mass in grams (e.g., 12g of C-12).

अव्होगाड्रो संख्या ही पुढीलपैकी गोष्टींशी संबंधित असते / The Avogadro number is related to

1)एखाद्या पदार्थाची 10³ मीटर मधील घनता. / Density of a substance in 10³ m

2)कोणत्याही पदार्थाच्या 1 ग्रॅम मधील रेणूसंख्या / Molecules in one gram of any material

3)1 mol मधील कोणत्याही पदार्थाच्या अणुकणांची संख्या / Atomic particles in 1 mol of any substance✓ Correct

4)एखाद्या पदार्थाच्या आण्विक वस्तुमानाची 10³ ग्रॅममधील C-12 मूळद्रव्यातील अणूंशी केलेली तुलना. / Atomic mass of a substance in comparison with 10³ grams of C-12 atoms.

Avogadro's number represents the total number of constituent particles (atoms or molecules) present in exactly 1 mole of any substance.

10 ग्रॅम वायुरूप हायड्रोजनमध्ये H₂, मानक दाब आणि तापमानात हायड्रोजनचे _________ मोल असतात. 10 g of gaseous hydrogen H₂, at NTP/STP contain _________ mol of hydrogen.

1)10

2)5✓ Correct

3)1

4)0.1

Number of moles is calculated as given mass divided by molar mass. Molar mass of H2 is 2 g/mol. So, 10 g / 2 g/mol = 5 moles.

ग्लुकोज मधे कार्बनची टक्केवारी __________ आहे. / The percentage of carbon in glucose is

a)40%✓ Correct

b)53%

c)45%

d)55%

The molecular formula of glucose is C6H12O6. Molar mass = (6*12) + (12*1) + (6*16) = 72 + 12 + 96 = 180 g/mol. Percentage of carbon = (72 / 180) * 100 = 40%.

यामध्ये सगळयात जास्त रेणू असतील. [H = 1, C = 12, O = 16, I = 127] The maximum number of molecules are present in _______ [H = 1, C = 12, O = 16, I = 127]

1)250 ग्रॅम आयोडीन स्फटिक / 250 g of iodine crystals

2)22 ग्रॅम कार्बन डायऑक्साइड / 22 g of carbon dioxide

3)45 ग्रॅम पाणी / 45 g of water

4)10 ग्रॅम हायड्रोजन वायु / 10 g of hydrogen gas✓ Correct

To find the maximum number of molecules, calculate the number of moles for each given option by dividing the given mass by its molar mass, then multiply by Avogadro's number. The substance with the highest moles will have the maximum molecules.

More Science & Technology concepts

Isotopes Chemistry Radioactivity Sound waves Taxonomy Atomic number Avogadro number Biodiversity Biology Molar mass Plant morphology Plant Pathology

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