Question

Which law of chemical combination is illustrated by the fact that 168 g Fe reacts with 72 g H2O to from 232g Fe3 O4 and 8g H2 ?

Answer 1

the law "law of conservation of mass" is illustrated by the fact that 168g Fe reacts with 72g H20 to form 232g Fe3O4 and 8g H2

Answer 2

Answer: law of conservation of mass

Explanation: According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products formed must be equal to the mass of reactants taken.

In order to get the same mass on both sides, the atoms of each element must be balanced on both sides of the chemical equation.

$3Fe+4H_2O\rightarrow Fe_3O_4+4H_2$

Mass of reactants= mass of $Fe$ + mass of $H_2O$=168g + 72 g= 240 g

Mass of products = mass of $Fe_3O_4$+ mass of $H_2$= 232 g+ 8 g= 240 g

Thus mass of reactants is equal to mass of products, thus law of conservation of mass is obeyed.