Answer:
<em>When molecular hydrogen (H2) and oxygen (O2) are combined and allowed to react together, energy is released and the molecules of hydrogen and oxygen can combine to form either water or hydrogen peroxide.</em>
Answer: Substance is Mercury (Hg)
number of protons = 80
number of electrons = 80
Explanation:
Atomic number which is symbolized by "Z" is the number of protons in nucleus of an atom.
Hence,
number of protons = atomic number = 80
- By knowing atomic number, we can find the element by using periodic table. Since the atomic number 80, the element is Mercury (Hg).
If the substance is in its neutral state, which means there is no charge on it, then the number of protons equals to the number of electrons of that element.
Hence,
number of electrons = number of protons = 80
The mass percent of oxygen in Nickel(
)sulfate is
percent.
At first, we look up the atomic masses for the element from the periodic table.
The atomic masses are found to be:
Next, we determine how many grams of each element are present in one mole of 
The mass of one mole
is:

So, The mass percent of oxygen 
percent.
To learn more about Mass percent, refer to:
1. Mechanical weathering
2. Reactions with oxygen
3. A rock that has been changed into one or more new compounds
Hope this Helps!!