How many moles of photons are contained in a burst of light that has wavelength 626. nm and contains 18.3 mJ of energy

What are the similarities of physical and chemical change ?

How can a give a full method for the experiment of separating sand from water by filtration? 1-materials 2-steps 3-conclusion also for water and salt separated by the evaporation or distillation process

What volume would 2.25 moles of ne has occupy at stp?