When copper (cu) and oxygen (o) combine, two different compounds are formed. the first compound contains 88.8% copper by mass, and the second compound contains 79.9% copper by mass. (note: assume a 100-gram sample of each ) show that cu and o combine with each other in conformity with the law of multiple proportions. the small whole number ratio of the mass of cu per gram of o in the first compound to the mass of cu per gram of o in the second compound equals correct: your answer is correct. : 1. this ratio indicates that cu and ocorrect: your answer is correct. with each other in conformity with the law of multiple proportions.(b) determine the empirical formulas of the compounds. compound 1: ?

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

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"

b.

the accuracy of the data.