A sample of sodium peroxide, Na2O2, was reacted with an excess of water.

2 Na2O2 (s) + 2 H2O (l) —> 4 NaOH (aq) + O2 (g)

All of the sodium peroxide reacted, and the oxygen was collected over water at 21 degrees Celsius. The barometric pressure was 771 mm Hg. However, the level of water inside the tube was 25.0 cm above the level of water outside the tube. If the volume of gas in the tube is 31.0 mL, how many grams of sodium peroxide were in the sample?

According to the solutions in the back of my Chemistry book, the answer is 0.194 g Na2O2. I can’t seem to figure out how to get this answer, though. Any help would be very much appreciated!

For cyclohexane compounds drawn in a chair conformation:   -axial bonds are vertical  -equatorial bonds are parallel to two bonds within the ring.  thus, as i assume the chair conformation is drawn:   -the x group is in an axial position, as are the five other vertical bonds.  -three axial bonds are on the top face of the ring  -the other three axial bonds are on the bottom face  the position of the second substituent on each ring carbon is equatorial.  gauche groups must be on an adjacent carbon such as carbon 6 and carbon 2, and also gauche groups are rotated by 60 degrees relative to each other.  drawing the newman projections for c1–c2 and c1–c6 aids in visualizing the groups that are gauche to the y group on c1.  click this link and watch some academic videos that may you more understand the topic 

Okay this will take 1 hour okay dont forget me.

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