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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=15 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=14 energy level to the n=5 energy level.

Which of the following when mixed with lithium sulfate (Li2SO4) will produce a precipitate?  SrI2 Fe(NO3)2 Pb(C2H2O2)2

Which of the following statements is/are true?  The electron configuration of sulfur (S) is [Ne]3s23p4 The electron configuration of tin (Sn) is [Kr]5s24d105p2 The electron configuration of antimony (Sb) is [Kr]5s25d104d3

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

A researcher runs an experiment that produces 113.4 g of aluminum sulfate when adding 23.7 g of aluminum to excess sulfuric acid according the the following equations.  What is the percent yield of the reaction?  2Al(s) + 3H2SO4(aq)