How many moles of NO2 are equivalent to 74.3 grams of
NO2?
(N = 14.01 g/mol, O = 16.00 g/mol)
[?] mol

What semimetal can form four single covalent bonds.

Apiece of copper has a temperature of 75.6 0c. when the metal is placed in 100.0 grams of water at 19.1 0c, the temperature rises by 5.5 0c. what is the mass of the metal?

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)