Answer:

Explanation:
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In this case, since the buffer is not given, we assume it is based off ammonia, it means the ammonia-ammonium buffer, whereas the ammonia is the weak base and the ammonium ion stands for the conjugate acid. In such a way, when adding HI to the solution, the base of the buffer, NH3, reacts with the former to promote the following chemical reaction:

Because the HI is totally ionized in solution so the iodide ion becomes an spectator one.
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Answer:
The Radius is the distance from the center outwards. The Diameter goes straight across the circle, through the center. The Circumference is the distance once around the circle.
Answer: 5
Explanation: add up all the electrons and it will amount to 23. Arranging by the old model for electronic configuration, we have : 2, 8, 8, 5
The last number being 5 represent its valence electron
<h2>Answer:</h2>
It means the waves collides and constructive interference occurred.
<h3>Explanation:</h3>
If the two waves coming from the opposite direction collide with each other, there are two way of their interference.
- Constructive interference: An interference which results in the increase in energy. And it is when crust of a wave comes on the crust of second wave.
- Destructive interference: An interference which results in decrease in energy of the resulting wave and colliding waves cancel the result of each other.
Hence in experiment there will be constructive interference.