A monatomic species that has I8 electrons and a net charge of 2^- has

• the same number of electrons as a neutral argon atom

• more protons than electrons

• 2 unpaired electrons

• 20 protons

Consider the following reaction:

xAs₂S₃ + yO₂ → zAs₂O₃ + wSO₂

What is y (the coefficientfor O₂) when this equation is balanced using whole number coefficients?

• 5

• 7

• 9

• 11

How many grams of MgCO, contain 24.00 g of oxygen? (The molar mass of MgCO₃ is 84.30 g mol^-1)

• 42.15 g

• 84.30 g

• 126.00 g

• 154.00 g

If the reaction of 1.0 mol NH₃ (g) and 10 mol O₂(g) 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(l) is carried to completion, then

• all the O₂(g) is consumed

• 4.0 mol NO(g) is produced

• 1.5 mol H₂O(l) is produced

• all the NH₃(g) is consumed

Two atoms are said to be isotopes if

• they have the same atomic number but different mass numbers

• they have the same number of neutrons but different mass numbers

• the sum of the number of protons and neutrons is the same, but the number of protons is different

• they have the same number of neutrons but different modes of radioactive decay

Sodium stearate is a salt and is used

• in gunpowder

• in paint

• to make soap

• to make fertilize

167.

The pure form of carbon is

• diamond

• graphite

• charcoal

• fullerene

Which one among the following is the chemical formula of gypsum which is an ingredient of cement?

• Ca₂SiO₄

• CaSO₄.2H₂O

• CaO

• CaSO₄.3H₂O

The bond which is present between water molecules is

• electrovalent bond

• covalent bond

• hydrogen bond

• van der Waals bond

Water is a good solvent. This is due to high

• dielectric constant ofwater

• surface tension of water

• specific heat of water

• heat of fusion of water