Each diagram below represents the nucleus of an atom. How many different elements are represented by the diagrams

Which equation obeys the law of conservation of mass? A. 2Fe+3O2 - -> 2Fe2O3 B. 4Fe+O2--> 2Fe2O3 C. Fe+O2--> Fe2O2 D. 4Fe+3O2--> 2Fe2O3

What type of chemical hazard results from incomplete combustion of petroleum-based chemicals and other organic substances? a. Polycyclic aromatic hydrocarbons b. Polychlorinated biphenyls c. Persistent organic pollutants d.

A solution contains a mixture of pentane and hexane at room temperature. The solution has a vapor pressure of 255 torrtorr. Pure pentane and hexane have vapor pressures of 425 torrtorr and 151 torrtorr, respectively, at room temperature.

How can you tell if a chemical change has occurred?

What is the answer, with the correct number of significant figures, for this problem? 4.392 g + 102.40 g + 2.51 g = ?

What evidence of a chemical reaction might you see in dropping an Alka-Seltzer tablet into a glass of water?

State hess's law. how is it used

When the name of a molecule ends in - ose, the molecule is a

How many moles are in. 12 grams of gold.

When lithium reacts with bromine to form the compound LiBr, each lithium atom: (1) gains one electron and becomes a negativelycharged ion (2) gains three electrons and becomes a negativelycharged ion (3) loses one electron and becomes a