Which of the following is always true when a substance undergoes a physical change?

a. the composition changes.

b. a change in color occurs.

c. no new substance is formed.

d. its specific gravity remains the same.

Explain the high surface tension and low vapor pressure of water in terms of the structure of the water molecule and hydrogen bonding

What is defined as the charge an atom would have in a compound if its bonding electrons were assigned to the more electronegative atom? a) reduction number b) valence c) oxidation number d) electropositivity

Massive amounts of destructive energy are released when a nuclear fission bomb explodes. Where does that energy come from? Hydrogen atoms fuse together into helium, releasing nuclear energy. Molecules are created, releasing chemical energy.

A compound is 54.53% C, 9.15% H, and 36.32% O. What is its empirical formula? The molar mass of the compound is 132 amu. What is its molecular formula?

In past scientist used stars and planets to determine time?

Why could the Bohr model not predict line spectra for atoms other than hydrogen?

Cryolite, Na3AlF6 (s), an ore used in the production of aluminum, can be synthesized using aluminum oxide. Balance the equation. 1.) Balance the equation - AlO3 (s) + NaOH (l) + HF (g) - ->Na3AlF6+H2O (g) 2.) If 17.5 kilograms of Al2O3 (s), 51.

The volume, in liters, of 538 g of CO2

What are two types of cold air masses that influence the weather in North America? Name them and describe their humidity.

Initial Volume (VI) Final Volume (Vf) = Object's volume =