Lecture 2 : Chemical reactions ; Uncertainty in Measurement ; Laws of Chemical Combinations

The reactant which is entirely consumed in reaction is known as limiting reagent.
In the reaction 2A + 4B → 3C + 4D, when 5 moles of A react with 6 moles of B,
then
(i) which is the limiting reagent?
(ii) calculate the amount of C formed?

What is the symbol for SI unit of mole? How is the mole defined?

What volume of 10M HCl and 3M HCl should be mixed to obtain 1L of
6M HCl solution?

Calculate the weight of lime (CaO) obtained by heating 2000kg of 95% pure
lime stone (CaCO3)

Write Postulates of Dalton’s atomic theory.

State Avogadro’s law.

Explain law of multiple proportions with an example.

State law of definite proportions.

What is the difference between precision and accuracy?

What is the SI unit of density? 

Chlorine is prepared in the laboratory by treating manganese dioxide (MnO₂) with aqueous hydrochloric acid according to the reaction

4HCl_(aq) + MnO_2(s) → 2H₂O_(l) + MnCl_2(aq) + Cl_2(g)

How many grams of HCl react with 5.0 g of manganese dioxide?

Calcium carbonate reacts with aqueous HCl to give CaCl₂ and CO₂ according to the reaction, CaCO_3(s) + 2 HCl_(aq) → CaCl_2(aq) + CO_2(g) + H₂O_(l)

What mass of CaCO₃ is required to react completely with 25 mL of 0.75 M HCl?

In a reaction

A + B₂ → AB₂

Identify the limiting reagent, if any, in the following reaction mixtures.

(i) 300 atoms of A + 200 molecules of B

(ii) 2 mol A + 3 mol B

(iii) 100 atoms of A + 100 molecules of B

(iv) 5 mol A + 2.5 mol B

(v) 2.5 mol A + 5 mol B

In a reaction

A + B₂ → AB₂

Identify the limiting reagent, if any, in the following reaction mixtures.

(i) 300 atoms of A + 200 molecules of B

(ii) 2 mol A + 3 mol B

(iii) 100 atoms of A + 100 molecules of B

(iv) 5 mol A + 2.5 mol B

(v) 2.5 mol A + 5 mol B

If the speed of light is 3.0 x 10⁸ m s^-1, calculate the distance covered by light in 2.00 ns.