Chemical Properties

Chemical properties are properties that are determined by changing the identity of matter. Some examples for chemical properties are how the matter reacts to air, to water, to an acid, to a

base, to other chemicals, and to heat.

For example, flammability is the chemical

property of how easily something will

burn or ignite. Heat of combustion is a

chemical property that defines how much

energy (as heat) is released when

something is completely burned for

combusted).

When a sample of silicon, which is a major

part of computer chips, is exposed to air, it

oxidizes (rusts). This means it forms silicon

dioxide or silica on the surface of the

sample. In order to prevent uncontrolled

oxidation, the components of computer

chips already have controlled layers of

silicon dioxide or silica on them.

A common theme here is that a chemical property only becomes evident or can be measured during or after a chemical reaction. To measure or observe a chemical property the substance

undergoes a chemical reaction and actually changes identity. When your old iron rail rusts (oxidized, it actually changes from iron to iron oxide (runt. You no longer have the same

substance that you started with

Q26. Find out some of the chemical properties of aluminum and iron are and describe them

here./nSolubility, the amount of substance that will

dissolve in a solvent, is a physical property we will

discuss more in Lesson 10.

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Viscosity, the measure of a fluid's resistance to flow is a

physical property. Liquids with low viscosity pour

faster than those with higher viscosity

Conductivity, the ability of a solid to act as an electrical conductor or an electrical insulator, is a physical property

Substances (such as metals) that readily conduct electricity are called electrical conductors

Substances (such as most non-metals) that do not allow electric current to flow are called insulators

Density, is a physical property, but we will discuss it next

Q27. Describe physical properties of aluminum and iron./nQ28. Imagine you want to create an art and craft project to be displayed in your garden. If

you have a choice to use either aluminum or iron for this project, which material would you

choose? Please, use the properties that you found for answers Q1 and Q2 to explain your

reasoning

Q29. List and define at least four more physical properties not mentioned above.

Density

Density in the oftence per unit kame. It is a derived unit. These are units that

You do not neure density directly, it is calculated after measuring the mass and volume of something Density does change whe

Ap

Dersity Ma

ab

Since the Sibase units for mass are klograme, and the infor

Another common way of expressing density is a percubic center

which is often abbreviated one of these two ways (1 cubic centimeter-1

ter

Solubility and intermpletuar forces (Chemi

Solubility

tempt Solublchy

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Q30. Assuming all measurements are under normal conditions (referred to as STP

or Standard Temperature and Pressure). Search and find the following information

(again you may find the Dynamic Periodic Table helpful).

• What is the density of 100.0 grams of sodium? What is the density of 128 kg

of sodium?

• What is the density of 100.0 grams of silver? What is the density of 128 kg of

silver?

• What does this tell you about the correlation of density to the quantity you

have of a substance?