GAT Subject Chemistry MCQs

An empirical formula shows the lowest integer ratio of elements.
It may differ from the molecular formula.

Stoichiometry uses balanced equations to relate amounts.
It supports mass, mole, particle, and gas calculations.

A molecular formula is a whole-number multiple of the empirical formula.
It applies to substances composed of discrete molecules.

Moles equal mass divided by molar mass.
18 g ÷ 18 g/mol = 1 mol.

Balancing follows conservation of atoms and mass.
Coefficients change amounts, not chemical formulas.

Mass equals moles multiplied by molar mass.
2×58.5 = 117 g.

Equation coefficients give stoichiometric ratios.
They may be interpreted as molecule or mole ratios.

Once the limiting reactant is used up, no more product can form.
Other reactants may remain in excess.

An excess reactant is supplied beyond the stoichiometric requirement.
Some remains when the reaction is complete.

Solutions are homogeneous mixtures.
Any sampled portion has approximately the same composition.

Heterogeneous mixtures contain distinguishable regions or phases.
Examples include sand in water and granite.

A physical change alters form or state without changing chemical identity.
Ice and liquid water are both H2O.