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CHAPTER 2 SECTION 1 1. Matter is described by its properties and may undergo changes. 2. Everything in the universe that you can see is made up of matter. Matter and Volume 1. All matter takes up space, therefore all matter has volume. 2. Objects with volume cannot occupy the same space at the same time. 3. The volume of a liquid can be measured using a graduated cylinder. 4. To determine the volume of a liquid, take a reading at the bottom of the meniscus. The reading will usually be in milliliters. 5. The meniscus is the curve at the surface of the liquid. 6. The volume of a solid object is determined by measuring the length, width, and height of the object and then calculating. 7. The formula to determine the volume of a square or rectangle is V=lx wx h 8. The formula to determine the volume of a cylinder is V = Π r2h 9. The basic units on volume are cubic meters. The basic unit may have a prefix in front of it. 10. To determine the volume of an irregularly shaped object, use the water displacement method. 11. Place the object in a graduated cylinder with a premeasured amount of water. Take a reading at the bottom of the meniscus. The units will usually be in milliliters. 12. The amount of water displaced by the object is equal to its volume. 13. The volume of liquids can be expressed in liters or cubic units because of the following mathematical relationship: 1 ml = 1 cm3 Matter and Mass 1. All matter has mass. 2. The mass of an object is the same, no matter where in the universe it is located. 3. An object’s mass only changes if the amount of matter making it up changes. 4. Weight is a measure of the force with which gravity pulls on an object’s mass. 5. Since weight is a force, the unit on weight is a newton (N). 6. All objects with mass exert a gravitational pull. 7. The strength of the gravitational pull on an object is determined by 2 factors: a. by the mass of the objects involved b. by the distance between the objects involved 8. The greater an object’s mass, the stronger the pull of gravity will be on the object and the greater the object’s weight will be. 9. For every 1 kg of mass an object has, gravity pulls on that object with a force of 9.8 N. 10. An object’s weight changes depending on where it is in the universe because gravity’s pull is not the same everywhere in the universe. 11. More massive planets such as Jupiter have stronger gravitational pulls, so your weight would be greater if you could stand on that planet. Inertia 1. Inertia is defined as the tendency of an object to resist a change in its motion. 2. Mass is a measure of inertia because the greater an object’s mass, the greater its inertia. 3. The greater an object’s mass the harder it is to stop or start moving. SECTION 2 1. Knowing the properties of an unknown object can help you determine the identity of the object. Physical Properties 1. A physical property is defined as a characteristic that can be observed or measured without changing the matter’s identity. 2. Examples of physical properties: color odor magnetism shape strength density boiling/melting point mass volume size conductivity solubility freezing point 3. Density is one of the easiest-to-identify properties. 4. The greater the density the greater the likelihood the matter will sink. The lower the density the greater the likelihood the matter will float. 5. The density of water is 1 g/ml (or 1 g/cm3). That is the standard to which all other densities are compared. Physical Changes Do Not Form New Substances 1. A physical change is defined as a change that affects only the physical properties of a substance. No change in identity occurs. 2. Examples of physical changes: change in size change in state change in shape dissolving SECTION 3 1. Besides physical properties, matter also has chemical properties. Chemical Properties 1. Chemical properties are defined as characteristics of matter that are based on its ability to change into new matter that has different properties. 2. Examples of chemical properties: flammability – ability to burn reactivity – ability to combine with other substances 3. Chemical properties are not as easily observed as physical properties. Chemical Changes and New Substances 1. A chemical change is where one or more substances are changed into new substances that have properties that are different than the original substances. 2. Chemical properties describe which chemical changes will and will not occur. 3. Chemical changes are the processes by which substances actually become new substances. 4. Examples of chemical changes: rust burning spoilage baking formation of a gas from a solid and a liquid formation of a solid from two liquids (precipitate) 5. Signs of a chemical change: color change odor change fizzing production of heat foaming emission of sound/light 6. Chemical changes change the identity of matter. Some chemical changes can be reversed by additional chemical changes. 7. Physical changes can usually be easily reversed.