Phosphoric acid, H3PO4 is titrated with KOH.  When the equation is balanced, what is the sum of all of the coefficients?

A ruby laser is used drill holes through diamonds.  The wavelength of the ruby laser is 680 nm.  What is the energy of one photon of this light?

What is the molarity of a solution made by mixing 9.06 g of potassium chlorate, KClO3 in enough water to make 425.00 mL of solution?

For the following reaction 9.25 g of nitrogen is reacted with 12.1 g of lithium.  What is the theoretical yield of lithium nitride?  N2(g) + 6 Li(s)

What volume (mL) of 0.0250 M barium hydroxide (Ba(OH)2) is need to reach the equivalence point when you have  250.0 mL of 0.137 M  hydrobromic acid (HBr)?

An erbium YAG laser is used in dentistry to remove cavities often without the need of an anesthetic.  The ER:YAG laser has a wavelength of 2940 nm.  What is the energy of one photon of this light?

A solution of AgNO3is titrated with 66.13 mL of 0.04155 M CaCl2 .  Which of the following statements are true?   silver chloride is a precipitate no reaction happens calcium nitrate is a precipitate   When the precipitate is dried and weighed, how much precipitate would there be?    there is no precipitate 0.7876 g 0.3938 g 0.4509 g

Which of the following statements is/are true?  The electron configuration of arsenic (As) is [Ar]4s24d103p3 The electron configuration of silicon (Si) is [Ne]3s23p2 The electron configuration of germanium (Ge) is [Ar]4s23d104p2  

Calculate the energy of a photon emitted by a hydrogen atom when the electron falls from the n=14 energy level to the n=5 energy level.

Calculate the energy of a photon emitted by a hydrogen atom when the electron falls from the n=15 energy level to the n=5 energy level.