<span>The answer is letter B. Melting is an endothermic change, because ice absorbs energy from its surroundings as it melts. The melting process absorbs heat energy that causes the ice to melt. Endothermic change is when it absorbs energy from its surrounding. The other choices are incorrect because exothermic change releases energy to its surrounding.</span>
Answer:
a
Explanation:
because it is matter . It has change in molèculaŕ level
Answer:
2. At pH near the pI, nearly all the molecules carry no net charge
Explanation:
The general equilibrium for a molecule with multiple ionizable groups could be:
H₃A⁺ ⇄ H₂A + H⁺ ⇄HA⁻ + H⁺⇄A²⁻ + H⁺
<em>Where each equilibrium has its own pKa</em>
The equilibriums in which H₂A are involved (The neutral molecule), are used to determine the isoelectrical point.
The isoelectrical point is defined as the value of pH in which the molecule has no net charge.
Thus, true option is:
<h3>2. At pH near the pI, nearly all the molecules carry no net charge</h3>
79,200 feet.
Just multiply the total miles times the amount of feet in a single mile.
15 X 5280 ft= 79,200 feet