Matter and Classification Grade 10 Physical Sciences PDF

MATTER AND CLASSIFICATION GRADE 10 PHYSICAL SCIENCES  MATTER All the objects that we see in the world around us, are made of matter. Matter is anything that has mass and takes up space. Different objects can be made of different types of materials (the mat...

MATTER AND CLASSIFICATION GRADE 10 PHYSICAL SCIENCES  MATTER All the objects that we see in the world around us, are made of matter. Matter is anything that has mass and takes up space. Different objects can be made of different types of materials (the matter from which objects are made). For example, a cupboard (an object) is made of wood, nails, hinges and knobs (the materials). The properties of the materials will affect the properties of the object. SOME OF THE PROPERTIES OF MATTER CLASSIFICATION OF MATTER  MIXTURES A mixture is a combination of two or more substances, where these substances are not bonded (or joined) to each other and no chemical reaction occurs between the substances. In a mixture, the substances that make up the mixture: a) are not in a fixed ratio b) keep their physical properties c) can be separated by mechanical means We can group mixtures further by dividing them into those that are heterogeneous and those that are homogeneous.  HOMOGENEOUS MIXTURES A homogeneous mixture is one that is uniform, and where the different components of the mixture cannot be seen. Examples: salt and water, the air we breathe, steel.  HETEROGENEOUS MIXTURES A heterogeneous mixture is one that consists of two or more substances. It is non-uniform and the different components of the mixture can be seen. Examples: Soil, oil in water, ice cubes in a drink… Any more examples??  CLASSWORK TODAY’S DATE TOPIC: MATTER AND CLASSIFICATION 1. What is matter? 2. State and define at least five properties of matter. 3. Which has more density, 10 kg of iron or 10 kg of feathers? Why? 4. What is a mixture? 5. Differentiate between homogenous mixture and heterogeneous mixture. HOMEWORK TODAY’S DATE  PURE SUBSTANCES Any material that is not a mixture, is called a pure substance. Pure substances include elements and compounds. It is much more difficult to break down pure substances into their parts, and complex chemical methods are needed to do this. Pure substances have a sharply defined (one temperature) melting or boiling point. Chromatography is the process of separating substances (pure and impure) into their individual components.  ELEMENTS An element is a pure substance, made up of only one type of atom that cannot be split up into simpler substances. The smallest unit of an element is the atom.  COMPOUNDS A compound is a pure substance formed by a chemical reaction between two or more different elements, the elements are joined together in a fixed ratio. An important characteristic of a compound is that it has a chemical formula, which describes the ratio in which the atom of each element in the compound occur (e.g 𝐻!𝑂, NaCl, 𝐶𝑎𝑆𝑂") HOMEWORK (TOPIC: PURE SUBSTANCES) DATE  NAMES AND FORMULAE OF SUBSTANCES The compound name will always include the names of the elements that are part of it. In a compound, the element that is on the left of the Periodic Table, is used first when naming the compound. The symbols of the elements can be used to represent compounds e.g. FeS, NaCl, KBr and 𝐻! 𝑂. These are called chemical formulae. A compound may contain ions (an ion is an atom that has lost or gained electrons). These ions can either be simple (consist of only one element) or compound (consist of several elements). Prefixes can be used to describe the ratio of the elements that are in the compound.  PREFIXES “mono” (one), “di” (two) and “tri” (three). 𝐶𝑂 (carbon monoxide) - There is one atom of oxygen for every one atom of carbon 𝑁𝑂! (nitrogen dioxide) - There are two atoms of oxygen for every one atom of nitrogen 𝑆𝑂" (sulphur trioxide) - There are three atoms of oxygen for every one atom of sulphur TABLE OF CATIONS(+) TABLE OF ANIONS SOME COMMON COVALENT COMPOUNDS  CLASS EXAMPLES 1. What is formula of sodium fluoride? 2. What is the formula for magnesium chloride? 3. Write the chemical formula for magnesium oxide. 4. Write the formula for copper(II) nitrate.  CLASSWORK DATE 1. Define the following terms: Atom, Cation and Anion. 2. With the aid of atomic structure, indicate how the following elements react together, state the name of the compound that is formed and the chemical formula. a. Sodium and Chlorine b. Magnesium and Chlorine c. Lithium and Oxygen d. Calcium and Fluorine e. Beryllium and Iodine f. Potassium Sulfide g. Calcium Chloride  CLASSWORK DATE 1. Complete the following table by giving the formulae of the compound formed by the two ions that corresponds to the block 𝑵𝒂! 𝑴𝒈𝟐! 𝑨𝒍𝟑! 𝑪𝒂𝟐! 𝑶𝑯$ 𝑺𝑶𝟒 𝟐$ 𝑪𝑶𝟑 𝟐$ 𝑷𝑶𝟒 𝟑$ 2. Write down the names of the following compounds: a. 𝑵𝑯𝟒$ b. 𝑯𝟑𝑶$ c. 𝑷𝑶𝟒 𝟑& d. 𝑺𝑶𝟑 𝟐& e. 𝑴𝒏𝑶𝟒& f. 𝑴𝒏𝑶𝟒𝟐& g. 𝑪𝑶𝟑𝟐& h. 𝑵𝑶𝟑& i. 𝑶𝑯& HOMEWORK (NAMES AND FORMULAE OF SUBSTANCES)  METALS, METALLOIDS AND NON-METALS The elements in the periodic table can also be divided according to whether they are metals, metalloids or non-metals. The zigzag line separates all the elements that are metals from those that are non-metals. Metals are found on the left of the line, and non- metals are those on the right. Along the line you find the metalloids. METALS  NON-METALS In contrast to metals, non-metals are poor thermal conductors, good electrical insulators (meaning that they do not conduct electrical charge) and are neither malleable nor ductile. The non-metals include elements such as sulphur (S), phosphorus (P), nitrogen (N) and oxygen (O).  METALLOIDS Metalloids or semi-metals have mostly non-metallic properties. One of their distinguishing characteristics is that their conductivity increases as their temperature increases. This is the opposite of what happens in metals. This property is known as semiconductance and the materials are called semi-conductors. Semi- conductors are important in digital electronics, such as computers. The metalloids include elements such as silicon (Si) and germanium (Ge). ELECTRICAL CONDUCTORS, SEMI-CONDUCTORS AND INSULATORS An electrical conductor is a substance that allows an electrical current to pass through it. An insulator is a non-conducting material that does not carry any charge. Semi-conductors behave like insulators when they are cold, and like conductors when they are hot. The elements silicon and germanium are examples of semi-conductors.  THERMAL CONDUCTORS AND INSULATORS A thermal conductor is a material that allows energy in the form of heat, to be transferred within the material, without any movement of the material itself. An easy way to understand this concept is through a simple demonstration. An insulator is a material that does not allow a transfer of electricity or energy. Materials that are poor thermal conductors can also be described as being good thermal insulators.  MAGNETIC AND NON-MAGNETIC MATERIALS Magnetism is a force that certain kinds of objects, which are called ‘magnetic’ objects, can exert on each other without physically touching. A magnetic object is surrounded by a magnetic ‘field’ that gets weaker as one moves further away from the object. A metal is said to be ferromagnetic if it can be magnetised (i.e. made into a magnet). If you hold a magnet very close to a metal object, it may happen that its own electrical field will be induced, and the object becomes magnetic.  CLASSWORK DATE 1. Define: electrical conductor, thermal conductor, insulator, semiconductor and magnetism Metals Metalloids Non-metals 2. Fill in the table with properties of metals, metalloids and non-metals. Metals Metalloids Non-metals 3. Substance Metal/non-metal Thermal Electrical Magnetic conductor conductor yes/no Yes/No Yes/No Aluminium Carbon rod Iron Nickel Copper Sulfur 4. How does the electrical conductivity of metals and metalloids change with an increase in temperature? LONG HOMEWORK TODAY’S DATE 10.How does the electrical conductivity of metals and metalloids change with an increase in temperature.