Iron (Fe) and diatomic oxygen (O2) combine to produce iron(III) oxide (Fe2O3). The table below compares the properties of these substances. Iron (Fe) Oxygen (O2) Iron(III) Oxide (Fe2O3) Melting Point (°C) 1538 −218.4 1565 Density (g/cm3) 7.83 0.00143 5.26 Appearance shiny, gray metal colorless, odorless gas red, odorless powder What can be concluded from this data? A. A chemical reaction occurred because iron(III) oxide has different properties than iron and diatomic oxygen. B. A chemical reaction occurred because iron(III) oxide has similar properties to iron and diatomic oxygen. C. A chemical reaction did not occur because iron(III) oxide is not a new substance. D. A chemical reaction did not occur because solid iron cannot chemically react with oxygen gas.

explanation:

the largest database of organic compounds lists about 10 million substances, which include compounds originating from living organisms and those synthesized by chemists. the number of potential organic compounds has been estimated at 1060—an astronomically high number. the existence of so many organic molecules is a consequence of the ability of carbon atoms to form up to four strong bonds to other carbon atoms, resulting in chains and rings of many different sizes, shapes, and complexities. the simplest organic compounds contain only the elements carbon and hydrogen, and are called hydrocarbons. even though they are composed of only two types of atoms, there is a wide variety of hydrocarbons because they may consist of varying lengths of chains, branched chains, and rings of carbon atoms, or combinations of these structures. in addition, hydrocarbons may differ in the types of carbon-carbon bonds present in their molecules. many hydrocarbons are found in plants, animals, and their fossils; other hydrocarbons have been prepared in the laboratory. we use hydrocarbons every day, mainly as fuels, such as natural gas, acetylene, propane, butane, and the principal components of gasoline, diesel fuel, and heating oil. the familiar plastics polyethylene, polypropylene, and polystyrene are also hydrocarbons. we can distinguish several types of hydrocarbons by differences in the bonding between carbon atoms. this leads to differences in geometries and in the hybridization of the carbon orbitals.

c.

explanation:

particle   p is an electron and particle q is a neutron