Between what two energy levels must an electron fall to emit a wavelength of 1094 nm?

What’s the percent by mass of carbon in c10h14n2

You are making a solution of calcium chloride dissolved in water. you add solid, stir, and it dissolves. you add just a spatula tip full, stir, and the solid does not dissolve. how could you describe the solutions before and after adding the spatula tip amount

Calculate the number of moles of ethane in 100 grams