Which change occurs when an atom in an excited

state returns to the ground state?

(1) Energy is emitted.

(2) Energy is absorbed.

(3) The number of electrons decreases.

(4) The number of electrons increases.

What came first, the orange or the color orange?

Water is a colorless and odorless liquid. It can exist in solid, liquid, and gas states. It boils at 100 degrees C and melts at 0 degrees C. Which option best describes this information?

The atoms in a sample are close together but can slide past one another. As the atoms lose energy, they move slower. The atoms become locked in place because of attractive forces between themwhich change of state is taking place?

What is an estimated number? a. An integer c. An exact number b. An imaginary number d. A measured numbe

Sometimes in the lab we collect the O2gas formed by a chemical reaction over water (see sketch at right). This makes it easy to isolate and measure the amount of gas produced. Suppose the gas evolved by a certain chemical reaction taking place at 55.

A saline solution contains 1.6 % NaCl by mass. How much NaCl is present in 57.2 g of this solution?

During a laboratory experiment you discover that an enzyme-catalyzed reaction has a delta G of - 20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the delta G for the new reaction

What is the molarity of a hydrochloric acid solution prepared by diluting 200.0 ml of 0.500m hcl to a total volume of 1.00 l?

How does a metallic bond differ from an ionic bond

Give two examples of chemical energy being transformed into electrical energy