What kind of property is density?

Question

answer these other questions if you have time...
-Why did Thomson change Dalton's atomic theory?
-What happens to the particles of a substance when it changes from a liquid to become a gas?
-What separates the chemical formulas of reactants from the formulas of reactants of the products in a chemical equation?
-Is salt water a compound? If not, then what is it?
-Copper turns green when it interacts with substances in the air. What kind of change is this?

Answer 1

Density in an intensive physical property.

Thomson used his cathode ray tube to discover that the atom was not a solid sphere as Dalton had thought. Thomson discovered that all atoms emitted electrons in the cathode ray tube.

When a liquid vaporizes the particles gain enough kinetic energy to overcome any attractive forces that are holding them in the liquid state. They will expand as they vaporize and take up about 1000 times more space.

An arrow (yield sign) is used to separate the reactants on the left and products on the right in a chemical equation.

Salt is a compound, and water is a compound. However, salt water is a homogeneous mixture which can be easily separated by evaporation.

When copper turns green it is a chemical change. The copper is chemically combining with oxygen from the air to make a compound known as copper oxide.

Answer 2

Using water as an example: the explanation is that different phases of matter are associated with different energy levels. Steam at 100°C is the same temperature, but contains much more thermal energy than liquid water at 100°C. The same goes for water and ice at 0°C. This is because molecules of water are much more free to move around as a gas than as a liquid, and that freedom of movement means there is much more kinetic energy associated with each molecule, and that energy is transferred as the substance shifts phase.

Salt water is a compound (H2O + NACl) water and sodium chloride

When copper turns green, it is oxidizing (reacting with the oxygen in the air) much like steel when it rusts or aluminum corrodes)

Answer 3

Density, or volumic m (ISO 31), is a physical property and is a measure of mass per volume. The average density of an object equals its total mass divided by its total volume. An object made from a comparatively dense material (such as iron) will have more mass than an equal-sized object made from some less dense substance (such as aluminium).
The mass per unit volume of a material. The term is applicable to mixtures and pure substances and to matter in the solid, liquid, gaseous, or plasma state. Density of all matter depends on temperature; the density of a mixture may depend on its composition, and the density of a gas on its pressure. Common units of density are grams per cubic centimeter, and slugs or pounds per cubic foot. The specific gravity of a material is defined as the ratio of its density to the density of some standard material, such as water at a specified temperature, for example, 60°F (15.6°C), or, for gases the basis may be air at standard temperature and pressure. Another related concept is weight density, which is defined as the weight of a unit volume of the material.
-Atoms were thought to be the smallest possible division of matter until 1897 when J.J. Thomson discovered the electron through his work on cathode ray tubes.[6] A cathode ray tube of the kind used by Thomson is a sealed glass container in which two electrodes are separated by a vacuum. When a voltage is applied across the electrodes, cathode rays are generated, creating a glowing patch where they strike the glass at the opposite end of the tube. Through experimentation, Thomson discovered that the rays could be deflected by an electric field (in addition to magnetic fields, which was already known). He concluded that these rays, rather than being waves, were composed of negatively charged particles he called "corpuscles" (they would later be renamed electrons by other scientists).


The density of a gas is highly dependent on the temperature and pressure, which relate to each other via the gas laws. In general, the density of a gas (in kg/m3) at a temperature of 0°C and pressure of 1 atm is approximately 0.0446 times the average molecular mass (in g/mol) of the gas; hence gas densities under these conditions range from about 0.09 kg/m3 (Hydrogen) to ca. 13.1 kg/m3(Tungsten(VI) fluoride).
-Brackish water (less commonly brac water) is water that is saltier than fresh water, but not as salty as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur as in brackish fossil aquifers. Certain human activities can produce brackish water, in particular certain civil engineering projects such as dikes and the flooding of coastal marshland to produce brackish water pools for freshwater prawn farming.
-Usually this is done with chemicals which oxidize the copper. First of all, the metal must be very clean. That means no traces of grease on the surface. To remove it, sandblasting is best, but detergent and pumice powder will work with lots of scrubbing- rinse well afterwards, and don't touch the surface with your hands. Remove residual oxides with acid dips or a substitute such as Sparex (sodium bisulphate) in a hot solution, which is less caustic.It is necessary to get the copper surface chemically clean, with any pre-existing oxides scrubbed off.

The patina chemicals can be sprayed on or applyed with a brush, but be careful to use one that doesn't have a steel ferrule, because this will contaminate the patina. Never get any iron into this solution- use copper tongs to remove small pieces, or attach a copper wire to big ones. Working in a very well-ventilated area- use an electric fan or two to move air past the piece and not into your face, get the piece hot with a soft flame, so that water splashed on will sizzle off (but don't get it too hot, or you will burn your green to brown.) When it is hot, spray on cupric nitrate solution (or a proprietary mixture of chemicals) with an airbrush or spraybottle. You can use a bristle brush, but they don't like the hot metal and the hairs tend to curl up at the ends.

Build up layers of green with repeated applications. In a half hour, it should be very green. Other methods involve making a tent with plastic to enclose the piece along with open containers of chemicals (the fume patina technique) or burying the piece in chemically treated sawdust or earth (a technique devised to imitate the patina found on long-buried bronze artifacts.) All these chemicals are toxic to a greater or lesser degree, so make sure you have some positive ventilation going when you apply the chemicals, especially if you are heating the piece previous to application, which accelerates the effect. There are proprietary formulations of patina chemicals available, or you can mix your own.

Answer 4

density is physical prop