Explanation:
<h2>The number of energy levels (n) increases, so there is a greater distance between the nucleus and the outermost orbital.</h2>
PbCl2 would not dissolve because it is insoluble based on the solubility rules for substances that will dissolve in water. This compound would instead form a solid precipitate at the bottom of the container.
The correct answers are
-formation of a precipitate
-bubble formation
-color change
-temperature change
-odor formation
The only one that isn’t correct is change in state of matter. A change in a state of matter does not mean it’s a chemical change. For example, water boiling so it turns into gas is not a chemical change, and is a physical one. Also, water can freeze and turn into ice, which is also still a physical change. If something changes state of matter, it does not necessarily mean it’s a chemical change.
Answer: There are 78.26 mL of a 0.0023M strontium hydroxide solution are needed to completely react 15.0 mL of 0.012M hydrochloric acid.
Explanation:
Given: 
= 0.0023 M, 
= ?
= 15.0 mL, 
= 0.012 M
Formula used to calculate volume of strontium hydroxide solution is as follows.
Substitute the values into above formula as follows.
Thus, we can conclude that there are 78.26 mL of a 0.0023M strontium hydroxide solution are needed to completely react 15.0 mL of 0.012M hydrochloric acid.
4. Static, sliding,rolling,and fluid friction
