What is the mass of snow (in tons) on a 150.0ft by 45.0 ft flat roof after a 6.0 inch snowfall? assume that 11 inches of snow is equivalent to 1.0 inches of water. the density of water is 1.00g/ml.

6 inches of snowfall would be equivalent to 6/11 inches of water or 6/132 feet. So the volume of the equivalent amount of water on the roof is 150 ft. x 45 ft. x 6/132ft. = 306.8 cubic feet.   
Since there are 907185 grams in a ton and 28316.8 mL in a cubic foot, 1.00 g/mL is equivalent to 0.0312 tons/cubic foot  
Multiplying the two results gives 9.58 tons of snow.

Which of the following did you identify correctly

The activity series is shown in the attached picture. if the element is below the other, then you can displace the other. following the activity series as a guide, the reactions are as follows: nickel and aluminum chloride3 ni + 2 alcl₃  → 3 nicl₂ + 2 albarium and copper bromideba + cubr  →  no reaction because cu is less oxidizable than bapotassium nitrate and aluminum3 kno₃ + al  → al(no₃)₃ + 3 ksodium phosphate and zincnaso₄ + zn  → znso₄ + na