0.7 g of iron combine directly with 0.4 g of sulphur to form FeS. If 2.8 g of Fe are dissolved in dilute HCl and excess of `Na_2S` solution is added, 4.4 g of FeS are precipitated. Show that these data prove law of constant composition.

0.7 g of iron reacts directly with 0.4 g of sulphur to form ferrous sulphide. If 2.8 g of iron is dissolved in dilute HCl and excess of sodium sulphide solution is added, 4.4 g of iron sulphide is precipitated. Prove the law of constant composition.

In an experiment, 2.4 g of Iron oxide on reduction with Hydrogen yields 1.68 g of Iron. In another experiment, 2.9 g of Iron oxide give 2.03 g of Iron on reduction with Hydrogen. Show that the above data illustrates the law of constant proportion.

A mass of 2.72 g of an alloy containing Pb, required for dissolved in HNO_3 containing 50% by mass of HNO_3 . When a H_(2)SO_(4) solution was added, 1.5 g of precipitate (A) appeared H_(2)S gas was then passed into the remaining solution a secfond precipitate was formed which when calcined in air produced 1.6 g of a compound B. Determine the composition of an alloy. (Al does not form Al_(2)S_(3) due to the hydrolysis of sulphide).

2.1g of Fe combines with S evolving 3.77KJ . The heat of formation of FeS in KJ//mol is

1.5 g of ethane (C_(2)H_(6)) on complete combustion gave 4.4 g of CO_(2) and 2.7 g of H_(2)O . Show that the results are in accordance to the law of conservation of mass.

4.0 g of NaOH and 4.9 g of H_(2)SO_(4) are dissolved in water and volume is made upto 250 mL. The pH of this solution is:

4.8 g of O_2 is mixed with 0.15 moles of Fe. Which of the following statements is/are correct ?

metal combines with oxygen to form two oxides, having the following composition: (i) 0.398 g of the first metal oxide contains 0.318g of metal. (ii) 0.716 g of the second oxide contains 0.636g of the metal. Show that the above data agrees with the law of multiple proportions.

What mass of sulphur is contained in 30 g of iron pyrites (FeS_(2))?

Calculate the work done when 112 g iron reacts with dilute HCl at 300 K. The reaction is carried out in an open container (At mass of Fe = 56)