Two processes are described below: process a: rapid moving water strikes a rock on the bottom of a stream and breaks it into pieces process b: glaciers moving along a rocky surface form cracks in the rocks which statement is true about the processes? a. both represent physical weathering. b. both represent chemical weathering. c. process a is physical weathering and process b is chemical weathering. d. process a is chemical weathering and process b is physical weathering.

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o