What do molecules and compounds have in common

Geologists pour acids on rocks to test for certain compounds. There are millions of different compounds around you. Probably everything you can see is one type of compound or another. When elements join and become compounds, they lose many of their individual traits. Sodium Na alone is very reactive. But when sodium and chlorine Cl combine, they form a non-reactive substance called sodium chloride table salt, NaCl.

New compounds have few or none of the physical or chemical traits of the original elements. They have a new life of their own. What about magnesium chloride MgCl 2? It contains one magnesium Mg and two chlorine Cl atoms. There are two ionic bonds. Methane CH 4 is made up of one carbon C and four hydrogen H atoms. There are four bonds and they are all covalent. Those examples have very simple chemical bonds. However, most compounds have combinations of ionic and covalent bonds.

List elements in the same group starting with the lower element and working up. From the information given, add a subscript for each kind of atom to write the molecular formula. Solution a The molecule has 4 phosphorus atoms and 3 sulfur atoms. Because the compound does not contain mostly carbon and hydrogen, it is inorganic.

Phosphorus is in group 15, and sulfur is in group Because phosphorus is to the left of sulfur, it is written first. Writing the number of each kind of atom as a right-hand subscript gives P 4 S 3 as the molecular formula. Ethyl alcohol contains predominantly carbon and hydrogen, so it is an organic compound.

The formula for an organic compound is written with the number of carbon atoms first, the number of hydrogen atoms next, and the other atoms in alphabetical order: CHO. It can be viewed as either an inorganic compound or an organic compound in which fluorine has replaced hydrogen.

The formula for Freon can therefore be written using either of the two conventions. According to the convention for inorganic compounds, carbon is written first because it is farther left in the periodic table. Fluorine and chlorine are in the same group, so they are listed beginning with the lower element and working up: CClF. Adding subscripts gives the molecular formula CCl 3 F. We obtain the same formula for Freon using the convention for organic compounds.

The number of carbon atoms is written first, followed by the number of hydrogen atoms zero and then the other elements in alphabetical order, also giving CCl 3 F. Nitrous oxide is used as a mild anesthetic for minor surgery and as the propellant in cans of whipped cream. Sucrose, also known as cane sugar, has 12 carbon atoms, 11 oxygen atoms, and 22 hydrogen atoms. Representations of Molecular Structures Molecular formulas give only the elemental composition of molecules. Hydrogen H 2 has a single bond between atoms.

Each bond represents an electron pair. Sulfur monochloride also called disulfur dichloride is a vile-smelling, corrosive yellow liquid used in the production of synthetic rubber. Its condensed structural formula is ClSSCl. Ethylene glycol is the major ingredient in antifreeze. Trimethylamine is one of the substances responsible for the smell of spoiled fish. Its condensed structural formula is CH 3 3 N. Given : condensed structural formula Asked for : molecular formula Strategy : Identify every element in the condensed structural formula and then determine whether the compound is organic or inorganic.

As appropriate, use either organic or inorganic convention to list the elements. Then add appropriate subscripts to indicate the number of atoms of each element present in the molecular formula.

Solution : The molecular formula lists the elements in the molecule and the number of atoms of each. A Each molecule of sulfur monochloride has two sulfur atoms and two chlorine atoms.

Because it does not contain mostly carbon and hydrogen, it is an inorganic compound. B Sulfur lies to the left of chlorine in the periodic table, so it is written first in the formula. Adding subscripts gives the molecular formula S 2 Cl 2. A Counting the atoms in ethylene glycol, we get six hydrogen atoms, two carbon atoms, and two oxygen atoms per molecule.

The compound consists mostly of carbon and hydrogen atoms, so it is organic. B As with all organic compounds, C and H are written first in the molecular formula. Dimerization makes it possible for a noble gas atom to link up with other atoms nearby or to make compounds in the laboratory.

This is demonstrated by the highly volatile compounds of platinum hexafluoride PtF6, xenon hexafluoroplatinate XePtF6, and xenon dioxide XeO2. Purity of a substance means the substance cannot be broken down any further without losing its unique physical and chemical properties.

Think of it as "the sum is greater than the individual parts. Breaking down that atom would only arrive at subatomic particles, not the atom itself. A compound is pure as well because it is made up of only one type of molecule. Breaking down a compound further would only lead to the individual atoms or individual elements that comprise that compound.

Particular physical and chemical properties are associated with pure substances. Breaking down those pure substances would only lead to components that have entirely different physical and chemical properties from the pure substance itself. In chemistry, homogeneous means that a substance has the same appearance and uniform composition throughout.

Put simply, a slab comprised of the element silver has only silver atoms throughout. Additionally, the entire slab exhibits both physical and chemical properties of the element silver. But a rusting slab of tin is not considered homogeneous. By the same token, the compound water is homogeneous when it is pure. If the water is contaminated, it is not homogeneous anymore, but heterogeneous. So a pure element and a pure compound are both homogeneous because they are untainted and retain all their properties consistently.