There are several differences between<span> a </span>physical and chemical change<span> in matter or substances. A </span>physical change<span> in a substance doesn't </span>change<span> what the substance is. In a </span>chemical change<span> where there is a </span>chemical<span> reaction, a new substance is formed and energy is either given off or absorbed.</span>
<span>B. Hydrogen is electrically neutralized in the solution. Hydrogen is a chemical element with symbol H and atomic number 1. With a standard atomic weight of circa 1.008, hydrogen is the lightest element on the periodic table.</span>
Answer:
isotope 2
Explanation:
it has the highest percentage abundance
Answer:
8 to 8.5 since that is the recommended and people usualy sleep more than that