Question

1. What amount of zinc acetate is required to make a 0.01 M solution of 20 ml volume? 2. What amount of sodium hydroxide is required to make 20 mL of 62.5 mM solutions? 3. What amounts of 62.5 mM sodium hydroxide solutions should be diluted with alcohol to make 40 mL of 20 mm, 15 mM or 10 mM solutions? 4. Using Equation 1 below, what mass of ZnO would be expected if 100% of the Zn from 10 mL of a 0.01 M solution precipitated? 5. If a nanoparticle suspension emits blue Naght (500 nm) what is the energy/mole of photons emitted? What is the energy/mole emitted for red Naght (625 nm)?

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Answer 1

o Molarity = moles of solute volume of solution (in L) of moles= 0.01 MX 120x/0-3 L) ") moles= 2x10-4 mol Now, mass= molesx molar mass of zine acetate of mass = lx1024 mol X 183.5 g/mol & mass = 0.0367 g Amount of rine acetate required = 0.0367 g)