Answer:The molecular formula of the oxide of metal be
. The balanced equation for the reaction is given by:

Explanation:
Let the molecular formula of the oxide of metal be 

Mass of metal product = 1.68 g
Moles of metal X =
1 mol of metal oxide produces 2 moles of metal X.
Then 0.03005 moles of metal X will be produced by:
of metal oxide
Mass of 0.01502 mol of metal oxide = 2.40 g (given)

y = 2.999 ≈ 3
The molecular formula of the oxide of metal be
. The balanced equation for the reaction is given by:

Answer: conversion of ice to steam
Explanation: Endothermic process is one in which energy is absorbed by the system.
Conversion of ice to steam is change of solid phase to gaseous phase, thus energy is required to break the strong inter molecular forces of attraction in solids to convert it into gaseous phase.
Conversion of steam to ice, conversion of steam to water and conversion of water to ice releases energy and are examples of exothermic processes.
The amount of chemical energy is equal to the amount of heat and light energy.
This is due to the principle of conservation of energy, which states that the total energy of a system remains constant.