Answer:
A and D are the answers
Explanation:
the other two don't make sense
Speed and velocity is a scalar and vector quantity of a similar parameter, respectively. They both refer to how fast an object moves. However, the speed only has to do with the magnitude. The velocity takes into account the sign which indicates the direction of the movement. For example, the value is -5 m/s. The speed is 5 m/s, but the velocity is 5 m/s moving downwards because the negative sign denotes downward movement or movement to the left.
Answer:

Explanation:
Half time is period required to desintegrating the half of the initial number of atoms. Then, the total time is:


C. pain reliever
ex. tylenol, aleve, etc.
Answer:
Choose the least electronegative atom other than H.
Explanation:
A Lewis structure consists of <em>terminal atoms</em> and one or more <em>central atoms</em>.
H can be <em>only a terminal atom</em> because it can form only one bond.
So the central atom must be either C or O.
The central atom is the less electronegative atom: C.
So, start the Lewis structure with a central C atom.
Then attach an O atom to get C-O.
Finally, attach the H atoms.
The condensed formula often gives you a clue where they go.
The formula CH₃OH implies that there are 3 H atoms on C and one on O.
The connectivity of the atoms is then as in the diagram below.