Ice crystallizes in hexagonal lattice. At a given temperature, the density of ice is 0.92 gcm -3. The
volume of unit cell is 1.3 x 10-22 cm". The number of H, Omolecules per unit cell is

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error

the answer is c.the valence of the atoms combine .