Chemical Equations and Stoichiometry

IMPORTANT

Chemical Equations and Stoichiometry: Overview

This topic covers concepts, such as, Stoichiometry and Stoichiometric Calculations, Calculations Involving Mole-mole Relation, Eudiometry & Calculation of Number of Moles by Eudiometry etc.

Important Questions on Chemical Equations and Stoichiometry

EASY
IMPORTANT

10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be:

HARD
IMPORTANT

The mass of carbon anode consumed (giving only carbon dioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is (Atomic mass: Al=27 ):

EASY
IMPORTANT

In the Haber process 30 litre of dihydrogen and 30 litres of dinitrogen were taken for reaction which yielded only   50% of the expected product. What will be the composition of gaseous mixture under the aforesaid condition in the end?

MEDIUM
IMPORTANT

In Haber's process, 30 litres of dihydrogen and 30 litres of dinitrogen were taken for the reaction, which yielded only 50% of the expected product. What will be the composition of the gaseous mixture under the aforesaid condition in the end?

EASY
IMPORTANT

Assuming full decomposition, the volume of  CO2 released at STP on heating  9.85 gofBaCO3 (Atomic mass,  Ba=137 ) will be:

EASY
IMPORTANT

Liquid benzene  (C6H6) burns in oxygen according to the equation

2C6H6(l)+15O2(g)12CO2(g)+6H2O(g)

How many litres of  O2 at STP are needed to complete the combustion of 39 g of liquid benzene?  (MolecularweightofO2=32,  C6H6=78)

EASY
IMPORTANT

Liquid benzene (C6H6) burns in oxygen according to the equation,

2C6H6(l)+15O2(g)12CO2(g)+6H2O(l)
How many litres of O2 at STP are needed to complete the combustion of 39 g of liquid benzene? (Molecular weight of O2=32, C6H6=78)

HARD
IMPORTANT

The stoichiometric reaction of 516 g of dimethyldichlorosilane with water results in a tetrameric cyclic product X in 75% yield. The weight (in g) of X obtained is ____________

[Use, molar mass gmol-1:H=1,C=12,O=16,Si=28,Cl=35.5]

 

HARD
IMPORTANT

2A+3B4C+5D

3C+4E5G + 6F

Starting with 7 mol of A6 mol of B and 8 mol of E, find the moles of G formed(yield=70%).

MEDIUM
IMPORTANT

1 g alloy of Cu and Zn reacted with excess of H2SO4 gives 60 ml of H2 at STP. What is the % of Zn in the alloy?

Atomic weight of Cu=63.5 u & Zn = 65.4

MEDIUM
IMPORTANT

56.0L of N2 gas is mixed with excess of H2 gas and it is found that 20L of NH3 is produced. The volume of unused N2 gas is found to be

HARD
IMPORTANT

When x grams of carbon are heated with y grams of oxygen in a closed vessel, no solid residue is left behind. Which of the following statement is correct?

HARD
IMPORTANT

10 mL of a gaseous hydrocarbon was exploded with sufficient oxygen. After explosion, there was a contraction of 20mL in volume. On shaking the residual gaseous mixture with KOH, there was a further contraction of 20mL in volume. Calculate the molecular formula. All the volumes were recorded at same temperature and pressure.

HARD
IMPORTANT

If the reaction sequence given below is carried out with 15 moles of acetylene, the amount of the product D formed (in g) is

Question Image

The yields of A,B,C and D are given in parentheses.

[Given: Atomic mass of H=1,C=12,O=16,Cl=35]

HARD
IMPORTANT

The treatment of an aqueous solution of 3.74 g of CuNO32 with excess KI results in a brown solution along with the formation of a precipitate. Passing H2S through this brown solution gives another precipitate X. The amount of X (in g) is____[Given: Atomic mass of H=1, N=14, O=16, S=32, K=39, Cu=63, I=127]

HARD
IMPORTANT

Calculate the millimoles of SeO32- in solution on the basis of following data:

70 ml of M60 solution of KBrO3 was added to SeO32- solution. The bromine evolved was removed by boiling and excess of KBrO3 was back titrated with 12.5 ml of M25 solution of NaAsO2.

The reactions are given below.

(a) SeO3+2-BrO3+-H+SeO4+2-Br2+H2O

(b) BrO3-+AsO2-+H2OBr-+AsO43-+H+

HARD
IMPORTANT

If 1.5 moles of oxygen combine with Al to form Al2O3, the mass of Al in g (Atomic mass of Al=27) used in the reaction is

HARD
IMPORTANT

In an experiment, pure carbon monoxide was passed over red-hot copper oxide. CO2, so produced, weighed 0.88 g and the weight of copper oxide was reduced by 0.3232 g. Calculate the atomic weight of carbon. [ Take molar mass of carbon dioxide =44g ]

MEDIUM
IMPORTANT

An alloy of aluminium and copper was treated with aqueous HCl. The aluminium dissolved according to the reaction Al+3H+Al3++32H2, but the copper remained as a pure metal. A 0.350 g sample of the alloy gave 415 cc of H2 measured at 273 K and 1 atm pressure. What is the weight percentage of Al in the alloy?

Give the final answer after rounding off to two significant figures.

HARD
IMPORTANT

When a mixture of NaBr and NaCl is repeatedly digested with sulphuric acid, all the halogens are expelled and Na2SO4 is formed quantitatively. With a particular mixture, it was found that the weight of Na2SO4 obtained was precisely the same as the weight of NaBr-NaCl mixture taken. Calculate the ratio of the weights of NaCl and NaBr in the mixture.

(Note: Report your answer after multiplying with 100 and rounding up to the nearest integer value.)