Answer:Chemical reactions often involve changes in energy due to the breaking and formation of bonds. Reactions in which energy is released are exothermic reactions, while those that take in heat energy are endothermic. exothermicA description of a chemical reaction that releases heat energy to its surroundings.
The molecular weight of water is <span>18.01528 g/mol.
So in 2.92 grams there are 2.92/</span>18.01528 = 0.1621 mol of particles.
1 mol contains 6,02214 × 10^<span>23 particles by definition.
So the nr of H2O molecules is </span>0.1621 * 6,02214 × 10^23 = 0,9761 × 10^23.
Every molecule has 2 H atoms, so you have to double that.
2* 0,9761 × 10^23 = 1.952 × 10^23.
Radiant energy to thermal energy
First convert volume to mass:
mass = 0.789 g/mL * 155 mL = 122.295 g
Then convert mass to number of moles:
number of moles = 122.295 g * (1 mole / 46 g) = 2.66 moles
Using avogadros number, we get the molecules:
<span>number of molecules = 2.66 moles * 6.022 x 10^23 molecules
/ mole = 1.6 x 10^24 molecules</span>
