Answer:
Electrons
Explanation:
Because the nucleas is In the middle and the Electrons surround it
The correct answer as to which observation most likely indicates that only a chemical change has taken place would that the change cannot be reversed.
When it comes to changes in a system, it can either be:
- physical change
- chemical change
When a substance undergoes a physical change, the original version of the substance can be recovered. In other words, physical changes can be reversible.
When a substance undergoes a chemical change, the original version cannot be recovered because an entirely new product would have been formed. In other words, chemical changes are irreversible.
Thus, once a change becomes irreversible, such a change is said to be a chemical change.
More on chemical change can be found here: brainly.com/question/1161517
Answer: c. At equilibrium, the concentration of reactants is greater than the products
Explanation:
Equilibrium constant for a reaction is the ratio of concentration of products to the concentration of reactants each raised to the power its stoichiometric coefficients.
For the reaction:
Equilibrium constant is given as:
![K_{eq}=\frac{[N_2O_5]}{[NO_2]\times [NO_3]}](https://tex.z-dn.net/?f=K_%7Beq%7D%3D%5Cfrac%7B%5BN_2O_5%5D%7D%7B%5BNO_2%5D%5Ctimes%20%5BNO_3%5D%7D)
![2.1\times 10^{-20}=\frac{[N_2O_5]}{[NO_2]\times [NO_3]}](https://tex.z-dn.net/?f=2.1%5Ctimes%2010%5E%7B-20%7D%3D%5Cfrac%7B%5BN_2O_5%5D%7D%7B%5BNO_2%5D%5Ctimes%20%5BNO_3%5D%7D)
When
a) K > 1, the concentration of products is greater than the concentration of reactants
b) K < 1, the concentration of reactants is greater than the concentration of products
c) K= 1, the reaction is at equilibrium, the concentration of reactants is equal to the concentration of products
Thus as 
is 
which is less than 1,
the concentration of reactants is greater than the concentration of products
Answer:
A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Physical properties include color, density, hardness, and melting and boiling points. A chemical property describes the ability of a substance to undergo a specific chemical change.
I hope this helps you understand! <3
Because it may not contain Hydrogen or Oxygen
