If your front lawn is 15.0 feet wide and 20.0 feet long, and each square foot of lawn accumulates 1450 new snow flakes every minute, how much snow (in kilograms) accumulates on your lawn per hour? assume an average snow flake has a mass of 1.70 mg. . it's my first college chm and i forgot how to do such word problems, would you me , you

First determine how many square feet there are in the front lawn. 
 (15.0 ft) x (20.0 ft) = 300. ft^2 
 Now find how many snow flakes land in the entire lawn. 
 (300. ft^2) x (1450 snow flakes/min/ft^2) = 435,000 snow flakes/min 
 Now find the total mass of snow landing on the lawn per hour. 
 (435,000 snow flakes/min) x (1.70 mg/snow flake) x (1 kg/1,000,000 mg) x (60 min/1hour) = 44.4 kg of snow per hour.