Element and compound baroe
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Here are the key points about homogeneous and heterogeneous mixtures: - Homogeneous mixtures have uniform composition and appearance throughout. Common examples include solutions. - Heterogeneous mixtures have visibly distinct parts that can be seen without using a microscope. The substances do not dissolve or blend uniformly. - Homogeneous mixtures are examples of single phase systems while heterogeneous mixtures contain two or more phases (solid, liquid, gas). - Sugar solution is an example of a homogeneous mixture where sugar is dissolved uniformly throughout the water. Water and oil is an example of a heterogeneous mixture since the substances do not dissolve in each other and remain as separate visible layers. The key difference is that homogeneous mixtures appear uniform while heterogeneous mixtures have distinct parts
Element and compound baroe
- 1. Elements ,compounds, and mixtures Juwarto, S.Pd Grade VII Semester 1 115 Junior high Schools
- 3. Basic Competency: To understand the element, compound and mixture. Standard Competency: Describes concept of element, compound and mixture. Objectives: • To describe the characteristics of elements, compounds, and mixtures • To classify matters into elements ,compounds ,and mixture
- 4. • Matter - anything that has mass and take any space
- 5. • Element is single matter that cannot be broken down into simpler matter by chemical methods. • There are 116 known elements. Of these 92 are found in the Earth (natural). The other 24 elements have been made by scientist in laboratories (manmade). Examples of element: silver Fluorine Gold Aluminium Mercury
- 6. The Symbol of element • Jons Jacob Berzelius proposed alphabets as the symbols of each element. • All of elements use symbol. These symbols were taken one or two letters from their old Latin or Greek name. Example: Au is the Latin word of gold “Aurum”. • Rules of writing element symbols: 1. If an element is symbolized by one letter, it must be capital letter, for example oxygen (O), hydrogen (H), carbon (C). 2. If an element is symbolized by more than one letters, the first letter must be capital letter followed by small letter, for example zinc (Zn), gold (Au), copper (Cu).
- 7. Think Time • What are the chemical symbols of the following elements? a) Bromine f) Mercury b) Silver g) Calcium c) Uranium h) Natrium d) Antimony i) Potassium e) Tungsten j) Helium • What are the names of the elements with the following chemical symbols? a) Si f) Ni b) P g) Al c) Sn h)Mg d) Pb i) Zn e) Au f) S
- 8. Classification of the Elements Classification of elements by state – Elements can be classified by their physical state at room temperature • Solid (of the 92 natural element, 79 are solids) • Gas (of the 92 natural element, 11 are gases) • Liquid (of the 92 natural element, 2 are liquid) Chlorine gaseous Silver solid element Bromine liquid element element
- 9. Classification of elements as metal and non – Elements are classified as metals and non-metals, depending metals on how well they conduct electricity and heat. – Metals are good conductors and Non-metal very poor electrical conductors. – Some elements are classified as Metalloids (or semi-metals). Metalloids have properties between those of metals and non metals. Metalloid metal Non - metal lead carbon sulphur boron mercury silikon copper chlorine neon Noble gases
- 10. Properties Metals Non-metals Ability to conduct Good conductor Poor conductor heat and electricity (except carbon) Densities, melting Usually solids Usually liquid and and boiling point (except gases with low mercury), high densities, low densities, high melting points melting points and boiling points and boiling points Appearance Usually hard and Usually soft and shiny dull Are they Yes No malleable? (mudah ditempa )
- 11. Classification of elements as in the periodic table
- 12. What are elements made of? • Atoms An atom is the smallest unit of an element, having properties of that element. The atoms of one element are different from the atoms of any other element. For example, all hydrogen atoms are the same and are different from atoms of carbon or iron. • Molecules Most gaseous elements form molecules comprising two atoms. Example: – Oxygen (O2), N2 Gases – Hydrogen (H2), – Nitrogen (N2), N + N N N – Chlorine (Cl2)
- 13. Post test Answer this question. • Define an element. • State the names and symbols of some common elements. • Describe ways of classifying the elements. www.chem4kids.com
- 14. • Compound is a substance containing two or more elements chemically joined together. • Compound is a single matter that cannot be broken down by physical separation. • The compound can only be broken down into its elements by a chemical reaction.
- 15. Ifelements combine together, they will completely change. For example: Water (H2O) is a compound made up of Hydrogen and Oxygen. Hydrogen and Oxygen are colourless gases, and the compound water is colourless liquid H H + O H O H
- 16. What are Compound made of? Molecules is the smallest particle of a compound. A compound contain only one kind of molecule. Molecule is a group of two or more atoms chemically joined together.
- 17. The chemical formula of a molecule shows the number and kinds of atoms contained in it. The chemical formula for water is Symbol of atom The amount of atoms present in one molecule This formula tells us that a water molecule contains 2 hydrogen atoms and 1 oxygen atom
- 18. 1. State the number of atoms and name the kinds of atoms shown by each formula a. Alcohol, C2H5OH b. Refined sugar, C12H22O11 c. Sulphuric acid, H2SO4 d. Sulphur dioxide, SO2 e. Glucose, C2H12O6 f. Urea, CO (NH2)2
- 19. Names of compound • Many compound contain a metal and a non-metal. The metal part usually comes first, followed by the non-metal part. – For example: NaCl (sodium chloride) • The names of many compounds with only two elements often end in –ide. – For example: MgO (magnesium oxide) • If the name of compound end in –ate, they contain oxygen. – For example: CaCO3 (Calcium Carbonate) • Acids are compounds. Their names usually end in –ic acid. – For example: HCl (Hidrochloric acid)
- 20. These are some of the chemical formula Compound Chemical Formula Sodium Chloride NaCl Magnesium Oxide MgO Sodium hydroxide NaOH Calcium carbonate CaCO3 Sulphuric acid H2SO4 Water H 2O Ammonia NH3 Carbon dioxide CO2 Sucrose (sugar) C12H22O11
- 21. Chemical reaction between hydrogen and oxygen producing water N BEFORE REACTION AFTER REACTION o Hydrogen Oxygen Water produced Excess 1 1 gram 8 gram 9 gram None 2 2 gram 16 gram 18 gram None 3 2 gram 8 gram 9 gram 1 gram of hydrogen 4 2 gram 17 gram 18 gram 1 gram of oxygen 5 3 gram 30 gram 27 gram 6 gram of oxygen 1. Calculate the comparison between the mass of hydrogen and oxygen in water compound. What is the result? 2. What will happen if the mass of hydrogen and oxygen reacting does not follow the comparison? 3. What can you conclude about the comparison of elements in the compound?
- 22. Conclusion a. Water was compound by hydrogen and oxygen with ratio of 1:8 (1 for hydrogen and 8 for oxygen) b. If the ratio of H:O was not equal to 1:8, there would be an excess element (sisa) c. The mass of elements before and after a mass ratio of elements of a “The reaction was CONSTANT compound component is constant” (Perbandingan massa unsur-unsur penyusun senyawa adalah tetap)
- 23. Think Time 1. When 4 grams of hydrogen react with 16 grams of oxygen, how many grams of water are produced? If there is an excess, determine the element and it mass Answer: • The comparison for the mass of N hydrogen and oxygen is 1:8 Before reaction After reaction o Hydrogen Oxygen Water produced Excess 1 4 gram 16 gram 18 gram 2 gram of (2 gram of hydrogen and 16 Hydrogen gram of oxygen)
- 24. • In the world, there are many things that’s not pure substances. • Mixtures consist of two or more substances that are not chemically joined together. • Mixtures can consist of elements, compound or both. Also the substances in a mixtures may be solids, liquids or gaseswater is mixture of Sea compounds including water Brass is a mixture of the and sodium chloride elements copper and zinc
- 25. Heterogeneou Homogeneou s s The prefixes "homo"- indicate sameness The prefixes: "hetero"- indicate A homogeneous mixture has the difference. same uniform appearance and A heterogeneous mixture consists composition throughout. Many of visibly different substances or homogeneous mixtures are phases. The three phases or states commonly referred to as of matter are gas, liquid, and solid. solutions. In sugar solution, sugar is the solute and water is the solvent
- 26. Compound Mixtures Composition Has a fixed composition Has a variable by mass composition by mass Melting and Has fixed melting and Has variable melting Boiling point boiling points and boiling points Properties Has it own properties Does not usually have which are different from its own properties; it its elements has the same properties as its component Separation Cannot be separated by Can be easily physical means. separated into its Chemical reaction is components by needed to separate the physical means. elements
- 27. Identify each of the following diagrams as an atom, molecule, element, compound or mixture.