Stoichiometry

1

How many moles of magnesium phosphate, Mg3(PO4)2 will contain 0.25 mole of oxygen atoms?

  1. 2.5 x 10-2
  2. 0.02
  3. 1.25 x 10-2
  4. 3.125 x 10-2
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2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

  1. decrease twice
  2. remain unchanged
  3. increase two fold
  4. be a function of the molecular mass of the substance
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3

With increase of temperature, which of these changes?

  1. molality
  2. molarity
  3. mole fraction
  4. weight fraction of solute
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4

What volume of hydrogen gas, at 273 K and 1 atm. pressure will be consumed in obtaining 21.6 g of elemental boron (atomic mass = 10.8) from the reduction of boron trichloride by hydrogen?

  1. 89.6 L
  2. 67.2 L
  3. 44.8 L
  4. 22.4 L
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5

Number of atoms in 558.5 gram Fe (atomic weight of Fe = 55.85 g mol–1) is

  1. twice that in 60 g carbon
  2. 558.5 × 6.023 × 1023
  3. half that in 8 g He
  4. 6.023 × 1022
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6

In the reaction,

2Al (s) + 6HCl (aq) → 2Al3+ (aq) + 6Cl (aq) + 3H2 (g)

  1. 6 L HCl (aq) is consumed for every 3 L H2(g) produced
  2. 11.2 L H2(g) at STP is produced for every mole HCl (aq) consumed
  3. 33.6 L H2(g) is produced regardless of temperature and pressure for every mole Al that reacts
  4. 67.2 L H2(g) at STP is produced for every mole Al that reacts
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7

The molecular formula of a commercial resin used for exchanging ions in water softening is C8H7SO3Na (Mol. Wt. 206). What would be the maximum uptake of Ca2+ ions by the resin when expressed in mole per gram resin?

  1. 2/309
  2. 1/103
  3. 1/206
  4. 1/412
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8

In a compound C, H and N atoms are present in 9:1:3.5 by weight. Molecular weight of compound is 108. Molecular formula of compound is

  1. C9H12N3
  2. C3H4N
  3. C6H8N2
  4. C2H6N2
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9

A sample of a hydrate of barium chloride weighing 61 g was heated until all the water of hydration is removed. The dried sample weighed 52 g. The formula of the hydrated salt is: (atomic mass, Ba = 137 amu, Cl = 35.5 amu)

  1. BaCl2.H2O
  2. BaCl2.2H2O
  3. BaCl2.3H2O
  4. BaCl2.4H2O
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