Brawley Middle Sixth Grade Science Matter: properties and change Christophe Fatton

1. Brawley MiddleSixth Grade ScienceMatter: properties and changeChristophe Fatton

2. Objectives 1 • Recognize that all matter is made up of atoms. • Recognize that atoms of the same element are similar, but different from atoms of other elements

3. Definition of Matter • anything that has mass and takes up space • Water in a bucket

4. Key concepts • Key Concepts • Chemistry is the study of matter. • Matter is made up of extremely tiny particles called atoms and molecules. • Atoms and molecules make up the three common states of matter on Earth—solids, liquids, and gases. • The particles of a liquid are attracted to one another, are in motion, and are able to move past one another. • Being a solid, liquid, or gas is a property of a substance.

5. Atoms and molecules • Atoms are the tiny particles that are considered to be the basic building blocks of all matter. • The nucleus is made of protons and neutrons. The shell has the electrons. The protons and electrons are positively or negatively charged. • Molecules are made of two or more atoms that are connected or bonded together.

8. Matter—Solid, Liquid, Gas • On Earth, matter is either found as a solid, liquid, or gas.

9. Matter—Solid, Liquid, Gas • particles (atoms or molecules) that make up the solid, liquid, and gas are moving •Matter (solid, liquid, and gas) is made up of tiny particles called atoms and molecules. •The atoms or molecules that make up matter are always in motion. •These first two ideas make up a very important theory called the Kinetic-molecular theory of matter. Basically the state of a sample of matter depends on TEMPERATURE!

10. Matter—Solid, Liquid, Gas • Atoms or molecules that make up solid, liquid or gas are attracted to one another

13. Properties of Matter • Matter has both physical and chemical properties. • It can also be classified according to these physical and chemical properties.

14. Matter’s Physical Properties • Physical properties: can be observed without changing the make-up, or identity, of matter.

15. Examples of Physical Properties

16. Physical properties cont..

17. Matter’s Chemical Properties • Chemical Property: ability to change new matter with different properties. • Chemical Property: new substance has chemical and physical properties different from the original substance. • Chemical reaction: When one or more substances change to form one or more new substances.

18. Chemical Property

19. Example of Chemical Properties

20. Physical and Chemical Changes • Physical change: only the physical properties of matter, but not the chemical properties. • Burning paper into ash • Chemical change: demonstrate that new substances can be made when two or more substances are chemically combined and compare the properties of the new substances to the original substances • You can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes. • Many common signs of a chemical change can be seen (bubbles forming, mass changed, etc).

21. Characteristics of Physical Changes • Melting point • Boiling point • Vapor pressure • Color • State of matter • Density • Electrical conductivity • Solubility • Adsorption to a surface • Hardness

22. Definitions • Melting point: the temperature at which a given solid will melt.

23. Definitions • Boiling point: The temperature at which a liquid boils and turns to vapor.

24. Definition • Volume: The quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance (solid, liquid, gas, or plasma) or shape occupies or contains. Volume is often quantified numerically using the SI derived unit, the cubic meter. LXWXH=V

25. Fahrenheit vs Celsius

26. Definitions • Density: the degree of compactness of a substance. D= m divided by volume • degree of consistency measured by the quantity of mass per unit volume.

27. Mass • Definition: A measure of how much matter is in an object. • Mass is commonly measured by how much something weighs. But weight can change depending on where you are (such as on the moon) while the mass stays the same. • Mass is measured in grams, kilograms and, tonnes(Metric) or ounces and pounds (US units)

28. Weight • Definition the force of gravity on the object and may be defined as the mass times the acceleration of gravity, w = mg • Gravity= 98.1 m/s2 (meter per second squared)

29. Characteristic of Chemical Changes • Reaction with Acids • Reaction with bases (alkalis) • Reaction with oxygen(combustion) • Ability to act an oxidizing agent • Ability to act as reducingAgent • Reaction with other elements • Decomposition into simpler Substances • Corrosion(corrodes)

30. Observations of chemical change • Formation of gas (bubbles) • Color change • Exchange of heat energy (endothermicexothermic reactions) • Production of light • Precipitate forms

31. Examples of Chemical change • Burning a log of wood • Frying or boiling an egg • Photosynthesis - a process in which carbon dioxide and water are changed into sugars by plants • Rotting of fruits • Roasting a marshmallow • Digestion of food • Moldy cheese • Souring of milk • Cracking heavy hydrocarbons to create lighter hydrocarbons • Burning of paper • Polymerization of gels • Different metabolic reactions in the cells • Decomposition of waste in a compost pit

32. Comparing Physical and Chemical Changes

33. Law of conservation of mass • Definition: mass is neither created nor destroyed during a chemical reaction – it is conserved. • Although chemical changes occurred, the total mass involved in the reaction remain constant. • Example: If you light a match, it converts the sulfur into gas, and leaves the carbon behind that was there originally, the whole time having the same original mass in the system.

34. Composition of Matter • Pure substance: usually referred to a substance • Definition: matter that has distinct properties and a composition that doesn’t vary from sample to sample. • Example of pure substance: it can be an element, compound or a mixture.

35. Substances Substances are either elements or compounds. • Elements: it cannot be decomposed into simpler substances. On the molecular level, each element is compose of only one kind of atoms.

36. Elements

37. Structure of an atom • Protons: positively charged subatomic particle located in the nucleus of an atom. It is counted to identify the atomic number • Neutrons: has the same amount of electrons as protons; they are equal. • Electrons: negatively charged subatomic particle located in the electron cloud.

38. The parts of an atom • http://www.iknowthat.com/ScienceIllustrations/atoms/science_desk.swf

39. Compound and Mixtures • Compound: substances composed of two or more elements, so they contain two or more kinds of atoms. • Mixtures: combinations of two or more substances in which each substance retains its own chemical identity.

40. Compound and mixture