2 C2H2 + 5 O2 --> 4 CO2 + 2 H2O
2.35 mol C2H2 - x mol O2
2 mol C2H2 - 5 mol O2

answer: 5.875 mol
When the number of protons and electrons are equal, that means the element is neutral. So, to know the element, find the element with an atomic number of 10. That would be Neon. Next, solve the mass number.
Mass number = protons +neutrons = 10+11 = 21
Thus, the expression should be written as shown in the attached picture.
Answer:
mixture
Explanation:
an example of one is a salad you can separate the ingredients