Answer: Out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.
Explanation:
A change that leads to the change in chemical composition of a substance is called a chemical change.
For example, 
Here, bond between the reactant atoms nitrogen and hydrogen is broken down.
On the other hand, bond connecting the products that is 
and 
is formed.
Thus,, we can conclude that out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.
Answer:
Please see the attached pictures.
Explanation:
☆ To ensure that each carbon has 4 bonds, fill the other bonds with Hs.
I am only in 6th grade so all I have to say is good luck and I wish you the best on that quiz.
Answer:
The hydrogen ion concentration of the substance is 3.16*10⁻⁵ M
Explanation:
pH is a parameter used to measure the degree of acidity or alkalinity of a substance. The pH is calculated as the negative logarithm (base 10) of the concentration of hydronium ions [H₃O⁺] or hydrogen ions [H⁺].
pH= - log [H₃O⁺]= - log [H⁺]
Values on the pH scale range from 0 to 14, where pH equal to 7 is neutral, below 7 is acidic and above 7 is basic.
In this case, pH= 4.5
So:
4.5= - log [H⁺]
Solving:
[ H⁺]= 10⁻⁴ ⁵
[H⁺]= 3.16*10⁻⁵ M
The hydrogen ion concentration of the substance is 3.16*10⁻⁵ M
Answer: The volume is 57.52 mL if the temperature if raised to 343K.
Explanation:
Given: 
= 27 mL, 
= 161 K
= ?, 
= 343 K
According to Charles law, at constant pressure the volume of an ideal gas is directly proportional to temperature.
Formula used is as follows.
Thus, we can conclude that volume is 57.52 mL if the temperature if raised to 343K.
