Pressure varies in the atmosphere because air molecules are being pulled down towards the center of the earth-hope this helps!
Yes, you should memorize them. While it is easy to predict them by looking at a periodic table, you should still have a strong grasp of simpler chemistry such as this before more challenging topics are taught.
<span>Which of the following is an electronic device that measures pH?
</span><span>a. a pH meter</span>
