I’m which organelle does photosynthesis take place

It occurs in the chloroplast. Thats why only plant cells have chloroplasts. 

Photosynthesis if you didn't know is taking sunlight, water, and carbon dioxide to create energy and Oxygen as a byproduct.

Photosynthesis occur mostly in plants and the organelle in which it takes place is the Chloroplast

Chloroplast

Hope I helped

6.72M of HNO3

Explanation:

In the problem you are diluting the original HNO3 solution by the addition of some water. The final volume is:

290.7mL + 350.0mL = 640.7mL

And you are diluting the solution:

640.7mL / 350.0mL = 1.8306 times

As the original concentration was 12.3M, the final concentration will be:

12.3M / 1.8306 =

6.72M of HNO3