When heat energy is added, two changes are observed:
Change A: Solid changes to a liquid
Change B: Solid changes directly to a gas.
What are the names for phase changes A and B?
A is freezing and B is condensation.
A is freezing and B is sublimation.
A is melting and B is condensation.
Ais melting and B is sublimation.

219 grams of iron (iii) oxide reacts with excess carbon according to the reaction equation shown below. fe2o3 + c → fe + co2 after a scientist performs the chemical reaction they find the actual yield of iron to be 57.4 grams. calculate the percent yield of this chemical reaction.

Your friend offers to show you an intrusive igneous rock. which of the following would you expect to see?

Sulfur dioxide and oxygen react to form sulfur trioxide during one of the key steps in sulfuric acid synthesis. an industrial chemist studying this reaction fills a 25.0l tank with 4.5 mol of sulfur dioxide gas and 4.5 mol of oxygen gas at 30.°c. he then raises the temperature, and when the mixture has come to equilibrium measures the amount of sulfur trioxide gas to be 1.4 mol. calculate the concentration equilibrium constant for the reaction of sulfur dioxide and oxygen at the final temperature of the mixture. round your answer to 2 significant digits.