1) The magnesium weighing 355g in a sample of water is first converted to MgNH4PO4 and then to Mg2P2O7. The mass of Mg2P2O7 obtained is 0.0870g. Express the quantity of magnesium in the mineral water in parts per million (that is, in g Mg per 10^6 g H2O).
a) 119ppm b) 53.5 ppm c)1.9 x 104 ppm d) 0.119ppm e) 26.8 ppm
2) A 10.0g sample of bismuth tribromide, BiBr3, contains:
a) 5.360 x 10^22 total number of ions b) 1.34 x 10^22 bromide ions
c) 0.322 mol BiBr3 d) 4.020 x 10^22 total number of ions e) 3.14 x 10^22 formula units BiBr3
3) A 2.0 gal flask weighs 4.0 lbs when empty. When its is filled with liquid, the flask weighs 4536.0 g. What is the density of the liquid in g/mL? (1 gal=3.785 L, 1 lb=453.6)
a) 0.72 g/mL b) 0.60 g/mL c) 0.36 g/mL d) 0.14 g/mL e) 0.071 g/mL