Answer: 
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
Thus in the reactants, there are 2 atoms of hydrogen and 2 atoms of iodine .Thus there has to be 2 atoms of hydrogen and 2 atoms of iodine in the product as well. Thus a coefficient of 2 is placed in front of HI.
The balanced chemical reaction is:

Different elements produce different colors of light when heated because the electrons in these elements have different permissible energy levels. When an element is heated, the electrons inside it become excited and move to an higher energy level from the ground state. When the electrons drop from this higher energy level, they typically emit energy quantum, the color of the light that is observed at this stage depends on difference that exist in the two energy levels.<span />
Answer: Chosen landforms are:
1) Hill
2) Mountain
3) Plateau
4) Valley
Explanation:
1) Hill is an elevated location smaller than a mountain. Location: Land
2) Mountain is a large mass of earth and rock, rising above the common level of the earth or adjacent land, usually given by geographers as above 1000 feet in height (or 304.8 metres).
Location: Land or Water
3) Plateau is a largely level expanse of land at a high elevation. It is also known as tableland.
Location: Land
4) Valley is an elongated depression between hills or mountains, often with a river flowing through it.
Location: Land or Water
<span>Copper metal (Cu) reacts with silver nitrate (AgNO3) in aqueous solution to form Ag and Cu(NO3)2. An excess of AgNO3 is present. The balanced chemical equation is shown below.
Cu + 2AgNO3 ---> Cu(NO3)2 + 2Ag
The molar mass of Cu is 63.5 g/mol. The molar mass of Ag is 107.9 g/mol. What mass, in grams, of Ag is produced from reaction of 31.75 g of Cu?
26.95
107.9
215.91
431.82</span>