The first question's answer is
At the half equivalence point [HA] = [A-] and pH = pKa
<span>if Ka is 5.2e-5 then pKa = pH = 4.28</span>
The answer is A. planning a hiking trip
A topographical map would not help studying plant growth over time unless you are looking for a better altitude to plant said plants.
A topographical map would not help studying rainfall for one year unless your location was <em>really</em> so high or low that it affected your weather
And most of all, a topographical map would not be useful for planning a cuise across the Atlantic Ocean because the elevation of the sea is zero!
A topographical map <em>would</em> be useful for planning a hiking trip because there are many factors and details that a hike should have. Which includes height, distance, paths, and elevation.
The atomic mass on the periodic table represents the sum of number of protons and number of neutrons.
Atomic mass = Number of protons + number of neutrons
Hope this helps!
