Igneous rock is formed by the cooling and solidification of molten Earth materials. Igneous rock forms when magma or lava cools. If igneous rock forms above ground after a volcanic eruption, it
forming
igneous rock, such as obsidian
which is a naturally occurring volcanic glass.
A)
cools quickly, extrusive
B)
cools quickly, intrusive
09
cools slowly, extrusive
D)
cools slowly, intrusive

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