A sample of a substance was heated strongly in a crucible, and the sample increased in mass. This is evidence that
A. a gas had been evolved.
B. the substance had melted.
C. the substance had sublimed.
D. a chemical change had taken place.
O E. a change of state had occurred.

Does the energy in a solid increase or decrease when changing to a liquid?

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)

Many free radicals combine to form molecules that do not contain any unpaired electrons. the driving force for the radical–radical combination reaction is the formation of a new electron‑pair bond. consider the chemical equation. n(g)+no(g)⟶nno(g) n(g)+no(g)⟶nno(g) write lewis formulas for the reactant and product species in the chemical equation. include nonbonding electrons. n(g)n(g) select draw rings more erase select draw rings more erase select draw rings more erase n no(g)