Classify each change as physical or chemical.

a. Natural gas burns in a stove.

b. The liquid propane in a gas grill evaporates because the valve was left open.

c. The liquid propane in a gas grill burns in a flame.

d. A bicycle frame rusts on repeated exposure to air and water.

Solution 47E: (a) We have to convert the speed of flies from m/s to Km/h We know The conversion factors are as follows 1000 m =1 km So, 1 km 15.2 m = 1000 m x 15.2 m And, 60 s = 1 min, 1 min 60 min 1 h = 60 min , 1 h Therefore speed of flies in km/h = 1 km x 15.2 mx 60s x 60 min 1000 m 1 min 1 h = 54.7 km/h 3 (b) The lung capacity of the blue whale is 5.0 * 10 L The conversion factors required for convert the volume from L to gallon are given below 1 gal = 3.7854 L 1 L = 1 gal/3.7854 1 gal The volume of 5.0 * 10 L = 5.0 * 10 Lx 3 3.7854 L= 1.3 x10 gal 3 3 Therefore, The lung capacity of the blue whale is 5.0 * 10 L is equal to 1.3 x10 gal (c) The Statue of Liberty is 151 ft tall Here, we have to convert the unit ft into m The conversion factors required for convert the ft to m are given below 1.0 ft = 0.0003048 km 0.0003048 km 1 ft 1 km =1 000 m 1000 m/ 1km 0.0003048 km 1000 m Therefore, 151 ft x 1 ft x 1 km = 46.02 m Thus, The Statue of Liberty is 151 ft tall is equal to 46.0 m d) Bamboo can grow up to 60.0 cm/day Here, we have to convert the unit cm/day to in/h The conversion factors required for convert the unit cm/day to in/h are given below We know, 1 in = 2.54 cm 1 in 1 cm = 2.54 cm 1 day = 24 h 1 day = 24 h Thus, Bamboo can grow up to 60.0 cm/day = 60.0 cm x 1 in x 1 2.54 cm 24 h = 0.984 in/h