Chlorine is the most electronegative
Answer: an ice pack getting cold (due to ammonium nitrate dissolving in water inside the pack)
Explanation:
Endothermic reactions: These are the reactions in which energy is required in the reaction. The energy of the products are more than the energy of the reactants.
Exothermic reactions: These are the reactions in which energy is released in the reaction. The energy of the products is less than the energy of the reactants.
a) water droplets condensing on a soda can on a hot summer day : As the gaseous molecules are changing into liquid phase, energy is released and is exothermic
b) an ice pack getting cold (due to ammonium nitrate dissolving in water inside the pack) : As the temperature is decreasing , energy is absorbed by the surroundings and thus is endothermic
c) thermite reaction between iron(III) oxide and aluminium (spectacular flames are observed) : As flames are produced, the energy is released and thus is exothermic
d) freezing water to make ice cubes : As the liquid molecules are changing into solid phase, energy is released and is exothermic
Answer: 0.19M
Explanation: 
Using Molarity equation:
= molarity of acid
= volume of acid
= molarity of base
= volume of base
Thus the concentration of the 
solution is 0.19M.
Explanation:
According to the law of conservation of mass, mass can neither be created nor destroyed but it can simply be transformed from one form to another.
For example, 
Mass of Na = 23 g/mol
Mass of Cl = 35.5 g/mol
Sum of mass of reactants = mass of Na + mass of Cl
= 23 + 35.5 g/mol
= 58.5 g/mol
Mass of product formed is as follows.
Mass of NaCl = mass of Na + mass of Cl
= (23 g/mol + 35.5) g/mol
= 58.5 g/mol
As mass reacted is equal to the amount of mass formed. This shows that mass is conserved.
As a result, law of conservation of mass is obeyed.
