Which of these indicate that a chemical reaction has occurred?

A.) Formation of a gas.

B.) Boiling of a substance.

C.) Melting of a substance.

D.) Freezing of a substance.

Describe one behavior that shows that light is a wave

In Hawaii, the mongoose was brought to the islands to control the snake population. It thrived, and now the mongoose population is rampant. Which threat to biodiversity describes this situation?

Consider the following reaction: 4NH3 (g) 7O2 (g) → 4NO2 (g) 6H2O (l) Consider an experiment in which you react ammonia and oxygen. At the end of the experiment, you find that you produced 27.0 g of water, and 8.52 g of ammonia is left over.

Why would it be colder in Aspen than it is in Denver?

Pluto is no longer considered to be a planet. Therefore, how many planets are in the solar system?

O2 + CS2 → CO2 + SO2 Which of the following shows the equation balanced?

Convert 970. mm Hg to atm.

The addition of a catalyst in a chemical reaction (A) increases the concentration of products at equilibrium. (B) increases the fraction of reactant molecules with a given kinetic energy.

Is fire hot or cold?

In Flask A, you reacted 7.23 g Mg with 1.05 mol HCl. In Flask B, you reacted 1.22 g Mg with 1.35 mol HCl. Which balloon will inflate the most?