Valence electrons are the electrons in the outermost shell. Those are t<span>he electrons on an atom that can be gained or lost in a chemical reaction.
</span>Elements that are left on the periodic table <span> have relatively few </span>valence electrons<span>, and can form ions more easily by losing their </span>valence electrons<span> to form positively charged cations.</span>
<span>Nonmetals are further to the right on the periodic table, so they gain electrons relatively easily and lose them with difficulty. </span>
Answer:
1. Elements
2. one
3. properties
4. Chemical
5. metal
6. non-metal
7. metalloids
8. Compounds
9. one
10. more
11. components
12. chemical process
Explanation:
In the given paragraph a brief about the difference between element and compound is given.
Elements are made up of the same type of atoms and each element is made up of one atom, that is they cannot be broken down into any other substance. Each element is different from each other due to its properties, though some have the same physical properties but are different in chemical properties. Elements can be classified as metals such as iron and silver, non-metals such as oxygen and hydrogen, and metalloids such as boron and silicon.
Compounds are a combination of one or more elements such as water and salt. Compounds can be easily broken down into components through a chemical process.
Hence, the correct answer is:
1. Elements
2. one
3. properties
4. Chemical
5. metal
6. non-metal
7. metalloids
8. Compounds
9. one
10. more
11. components
12. chemical process
Since the reaction gives off heat energy it is considered to be an exothermic reaction
Answer:
The standard enthalpy of formation of NOCl(g) at 25 ºC is 105 kJ/mol
Explanation:
The ∆H (heat of reaction) of the combustion reaction is the heat that accompanies the entire reaction. For its calculation you must make the total sum of all the heats of the products and of the reagents affected by their stoichiometric coefficient (number of molecules of each compound that participates in the reaction) and finally subtract them:
Enthalpy of the reaction= ΔH = ∑Hproducts - ∑Hreactants
In this case, you have: 2 NOCl(g) → 2 NO(g) + Cl₂(g)
So, ΔH=
Knowing:
- ΔH= 75.5 kJ/mol
= 90.25 kJ/mol
= 0 (For the formation of one mole of a pure element the heat of formation is 0, in this caseyou have as a pure compound the chlorine Cl₂)
=?
Replacing:
75.5 kJ/mol=2* 90.25 kJ/mol + 0 -
Solving
-=75.5 kJ/mol - 2*90.25 kJ/mol
-=-105 kJ/mol
=105 kJ/mol
<u><em>The standard enthalpy of formation of NOCl(g) at 25 ºC is 105 kJ/mol</em></u>
Varuable, In algebra, a symbol (usually a letter) standing in for an unknown numerical value in an equation :)
