Answer:
The amount of drug left in his body at 7:00 pm is 315.7 mg.
Explanation:
First, we need to find the amount of drug in the body at 90 min by using the exponential decay equation:

Where:
λ: is the decay constant = 
: is the half-life of the drug = 3.5 h
N(t): is the quantity of the drug at time t
N₀: is the initial quantity
After 90 min and before he takes the other 200 mg pill, we have:

Now, at 7:00 pm we have:

Therefore, the amount of drug left in his body at 7:00 pm is 315.7 mg (from an initial amount of 400 mg).
I hope it helps you!
The compound NaH2PO4 name is
sodium dihydrogen phosphate
Explanation
This name is arrived at by using the IUPAC rules of naming compound
1. the metal (sodium)is named first followed by the ligand ( hydrogen and phosphate)
Ligand are molecules that are attached to the metal center.
2. ligand are named using alphabetical order(for our case h for hydrogen come before p for phosphate hence hydrogen is named first)
3. Prefix di is used since hydrogen are two
hence the name of the compound is Sodium dihydrogen phosphate
Answer:
According to my research A molecule is two or more atoms held together by covalent bonds. An atom is the smallest part of an element. ... A sodium atom has one outer electron, and a carbon atom has four outer electrons.
Explanation:
The correct answer is (b) political map
The explanation:
when a political map: is different than other types of maps because it focuses on government or administrative boundaries rather than geographical or physical features. Instead of showing viewers what exists in the land, it shows those imaginary lines that serve to separate countries, states, territories, and cities. These maps generally include larger bodies of water, such as oceans, rivers, and lakes, as landmarks.
It was made by man not natural like the others maps.
so this is the correct answer.