Answer: The atoms of the solid products are tightly packed whereas those in gas are loose.
Explanation:
Atoms in the solid structure are linked to each other by strong force of attraction and they collectively form an three-dimensional structure. The binding of the atoms form the shape of the solid product. The gas exhibit free atoms in it. The atoms are not linked to one another by strong force of attraction. The atoms as a part of gas have higher energy as those present in the solid products. So, the atoms of the gas wander freely as compared to those in the solid products.
The mass of oxygen and hydrogen must be equal to the mass of the substance they create the water. So if the hydrogen is 2.8 g the oxygen must account for the rest of the mass. Basically just subtract 25.4-2.8=mass of oxygen
Atoms are the smallest building block that can affect things, and are many many times smaller then cells. our eyes are not designed to see such small things