In balancing reactions, the number of atoms on each side should be of equal number. It is the most important rule in reactions. Also, we should know the correct substances involved in the reaction. We do as follows:
2K + MgBr2 = 2KBr + Mg
all the elements in group 18 are Nobel gases or inert gases . all the elements such as neon , helium, argon etc. ,their outermost shell is completely filled . The noble gases have the largest ionization energies, reflecting their chemical inertness
Explanation:
The word equation for the burning of a candle is wax plus oxygen yields carbon dioxide and water. This is an exothermic reaction that produces both light and heat.
The fuel for a burning candle is the wax. There are many different types of wax with a corresponding number of chemical formulas, but they are all hydrocarbons. Hydrocarbons are molecules made from hydrogen and carbon.
Burning the wax pulls the hydrogen and carbon in the wax apart and recombines them with oxygen from the atmosphere. This is an oxidation reaction. The resulting carbon dioxide and water are gases that disperse in the air.
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The given question is incomplete. The complete question is:What is the relative atomic mass of a hypothetical element that consists isotopes in the indicated natural abundances.
Isotope mass amu Relative abundance
1 77.9 14.4
2 81.9 14.3
3 85.9 71.3
Express your answer to three significant figures and include the appropriate units.
Answer: 84.2 amu
Explanation:
Mass of isotope 1 = 77.9
% abundance of isotope 1 = 14.4% = 
Mass of isotope 2 = 81.9
% abundance of isotope 2 = 14.3% = 
Mass of isotope 3 = 85.9
% abundance of isotope 2 = 71.3% = 
Formula used for average atomic mass of an element :

![A=\sum[(77.9\times 0.144)+(81.9\times 0.143)+(85.9\times 0.713)]](https://tex.z-dn.net/?f=A%3D%5Csum%5B%2877.9%5Ctimes%200.144%29%2B%2881.9%5Ctimes%200.143%29%2B%2885.9%5Ctimes%200.713%29%5D)

Therefore, the average atomic mass of a hypothetical element that consists isotopes in the indicated natural abundances is 84.2 amu
Answer:The law of conservation of matter says that matter cannot be created or destroyed. In chemical equations, the number of atoms of each element in the reactants must be the same as the number of atoms of each element in the products. ... There are two oxygen atoms in the reactants and two atoms of oxygen in the product.
Explanation: