Which two gases make up most of the atmosphere?

What is a decay series? A. A chart that lists isotopes by how likely they are to decay. B. When an unstable isotope begins to decay and emits particles that cause atoms around it to become unstable. C.

A student boils 9.43 grams of an unknown substance into vapor. If completely vaporizing the substance required 8,720 joules of energy, what is the heat of vaporization?

Q 3.6: calculate the number of po43 - ions present in 23.7 g of ca3 (po4) 2.

The oxidation numbers of Fe and Br in the compound FeBr2

After 62.0 min, 33.0% of a compound has decomposed. What is the half-life of this reaction assuming first-order kinetics?

In an endothermic reaction, heat is absorbed from the surroundings. How does this affect entropy? A. The particles in the surroundings move slower and have decreased entropy. B.

The temperature of a sample of liquid water changes from 50°C to 30°C. Which statement best explains the change that must happen at the molecular level? A. The molecules move more quickly and their average kinetic energy increases. B.

The most important reason why solid sodium hydroxide is not used as a primary standard is

plate a and plate b are both continental plates. what is ghe most likely result if the two plates collide?

According to the second law of thermodynamics, the entropy of any system always increases. According to the second law of thermodynamics, the entropy of any system always increases. True False