PS-3.1 Distinguish chemical properties of matter (including reactivity) from physical properties of matter (including boiling point, freezing/melting point, density [with density calculations], solubility, viscosity, and conductivity).
Physical property: boiling point, freezing/melting point, density, solubility, viscosity, conductivity
Chemical property: the capacity to oxidize, combustibility, the capacity to corrode
If you have studied rocks and minerals, you may already be familiar with the physical properties that are used to identify minerals, such as color, luster, density, and streak. By definition, a physical property is a property or characteristic that can be observed without changing the chemical makeup of the substance. For instance, the boiling point of ethyl alcohol is 78.5oC. Boiling point is a physical property because the alcohol vapor produced in the boiling process still has the same chemical formula (C2H6O) that is had as a liquid. Boiling temperature is a physical property that, along with other physical properties, can be used to identify ethyl alcohol. Here are some common physical properties.
Boiling point- The temperature at which a substance boils when heat energy is added.
Condensation point- The temperature at which a gas (vapor) changes into a liquid when heat energy is removed.
Melting point- The temperature at which a solid becomes a liquid when heat energy is added.
Freezing point- The temperature at which a liquid becomes a solid when heat energy is removed.
Density- Density is the ratio between a samples mass and volume. D=m/v. An understanding of density begins with a deep understanding of mass. Mass is a measure of the quantity of matter an object contains. The quantity of matter an object contains depends upon the number of Protons and Neutrons ( subatomic particles) the sample contains. Obviously, 1cm3 of Gold is less massive than 5cm3 of Gold. This is because a 5cm3 sample of Gold contains more subatomic particles ( Protons and Neutrons) than the 1cm3 sample. By the same token, a 1cm3 sample of gold has a greater mass than a 1cm3 sample of Aluminum, because 1cm3 of Gold contains more sub atomic particles than 1cm3 of Aluminum. Gold atoms contain, on average, 197 subatomic particles each, while each Aluminum atom only contains an average of 26.98 subatomic particles.
Here are several examples of density problems you similar to those you should be able to solve. Remember, when finding density in the lab, mass can generally be found directly by using a triple beam balance. The volume of irregularly shaped solids can be found by using a graduated cylinder and the water displacement method.
A sample of matter was found to have a volume of 340.0cm3 and a mass of 80.0g. What is the density of the sample?
What is the mass of a sample that has a density of 13.00g/cm3 and a volume of 12.5cm3?
What is the volume of a sample that has a density of 10.0g/ml and a mass of 8.0g?
Color- The color of a sample is determined by the wavelength of light that is reflected from its surface or transmitted through it..
Solubility- The capacity of a substance to dissolve in a particular solvent at a given temperature. Solubility is often measured in units of grams of solute per 100ml of solvent at a given Celsius temperature.
Viscosity- The resistance of a substance to flow. High viscosity liquids flow slower than low viscosity liquids.
Electrical conductivity- Conductivity refers to the ability of a material to conduct electricity. In general, metals are good conductors as compared to non-metals.
Chemical properties are observable only while chemical changes are taking place. For instance, one chemical property of Hydrogen is that it will oxidize ( burn) rapidly with Oxygen to produce water vapor. Click here to see the result of a balloon filled with Hydrogen gas being ignited. In the video, the water vapor produced simply joins the water vapor in the atmosphere. Though no liquid water is seen, it is a product of the reaction. The capacity to combine chemically with Oxygen is a chemical property. The new substance, water vapor, formed while observing the property, no longer has the physical properties of Hydrogen gas. The water now has a new set of physical properties all its own.
Reacts with Oxygen to produce
water: 2H2+O2--> 2H2O
Reacts with Hydrogen to produce
water: 2H2+O2--> 2H2O
Not reactive in the presence of Oxygen. Reacts rapidly with Alkali metals to produce metallic oxide. Reacts less rapidly with other metals, such as Aluminum, to produce Oxides.
Colorless, odorless, elemental gas, at room temperature.
Density at 0 °C: 0.08988 g/L
Boiling Point: −252.87°C
Melting Point: −259.14°C,
Colorless, Odorless, elemental gas, at room temperature.
Density at 0 °C: 1.429 g/L
Boiling Point: -182.95°C
Melting Point: -218.79°C,
Almost colorless (slightly blue), odorless liquid compound, at room temperature.
Boiling Point: 100 °C
boiling Point: 0 °C