Stoichiometry

How many moles of magnesium phosphate

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

If we consider that 1/6, in place of 1/12, mass of carbon atom

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

With increase of temperature, which of these changes

With increase of temperature, which of these changes?

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

What volume of hydrogen gas, at 273 K and 1 atm

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

Number of atoms in 558.5 gram Fe

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

In the reaction, 2Al (s) + 6HCl (aq)

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

The molecular formula of a commercial resin used for exchanging ions

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

In a compound C, H and N atoms are present in 9:1:3.5 by weight

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

A sample of a hydrate of barium chloride weighing 61 g was heated until all the water of hydration is removed

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