Answer:
1.5M
Explanation:
Molarity = moles/volume
0.60 mol / 0.40 L = 1.5 M
Number of moles = 5.7 moles of oxygen.
<u>Explanation:</u>
We have to convert number of molecules into number of moles by dividing the number of molecules by Avogadro's number.
Here number of molecules of oxygen given is 34.1 × 10²³ molecules.
Now we have to divide the number of molecules by Avogadro's number as,
Number of moles = 
= 
= 5.7 moles
So here molecules is converted into moles.
The time elapsed when the ball placed above the concave mirror and the image formed would be at the same location is 0.55 s.
<h3>Image distance</h3>
The position of the image formed is determined using the followimg mirror formula;

where;
- f is the focal length of the mirror
- v is the image distance
- u is the object distance
f = R/2
f = 1.5/2
f = 0.75 m
When the ball and its image is in the same position, u = v
The position of the ball is calculated as;

<h3>Time of motion of the ball</h3>
The time taken for the ball to travel the caluclated distance is determined as;
h = ut + ¹/₂gt²
1.5 = 0 + ¹/₂(9.8)t²
1.5 = 4.9t²
t² = 1.5/4.9
t² = 0.306
t = 0.55 s
Thus, the time elapsed when the ball and its image are at the same location is 0.55 s.
Learn more about concave mirror here: brainly.com/question/7512320
The process is called freeze-thaw. 1st, liquid water gets into small holes or cracks in the rock (such as by rain or sea water splashing into them). 2nd, when the temperature drops this water will freeze into solid ice, because ice occupies more room than water this state change puts pressure and tension on the surrounding rocks. 3rd, when the temperature increases again the ice will melt back into water. It is this pressure increase and release than causes the rock to weather.