<p> CHEM ESSENTIAL CONCEPTS CHAPTER 1: THE PUZZLE OF MATTER. Obj 1.1 Define Chemistry and Matter, and explain the law of conservation of mass (problems p 46 #1, 6)</p><p> Chemistry is: ______</p><p> Matter is anything that has ______(takes up space) and ______(a measure of amount or quantity). Examples of matter are all the ______that make up the stuff of our world.  Law of conservation of mass (or matter): ______.</p><p>Obj 1.2 Classify matter according to its composition (problems p 46 #15, 17, 18, 29, 38, 39) Obj 1.3 Distinguish among elements, compounds, homogeneous mixtures and heterogeneous mixtures.</p><p> Substances are pure, and include elements (______) and compounds (______). Examples of substances are carbon (symbol </p><p>C) and hydrogen (H), which are elements; and carbon dioxide (CO2) and water (H2O), which are compounds.  Mixtures are made up of variable combinations of elements and/or compounds. Mixtures can be made up of substances evenly mixed throughout (called______mixtures, also known as ______) or mixtures can be made of substances that are combined but not dissolved (called ______mixtures). Examples of homogeneous mixtures are: ______. Examples of heterogeneous mixtures are ______.</p><p>Obj 1.4 Distinguish between physical and chemical properties (problems p 46 #7, 8, 14)</p><p> Physical properties are those that are characteristic of a sample of matter without ______.  Quantitative physical properties (______) include ______.  Qualitative physical properties (______) include ______.  Chemical properties describe______. A chemical property of iron is that it reacts with oxygen to form iron oxide (rust).</p><p>Obj 1.5 Contrast chemical and physical changes (problem p 46 # 16)</p><p> Chemical changes (also called ______) occur when substances are changed into other substances. When plants convert carbon dioxide and water to glucose and oxygen, a chemical change takes place. All chemical reactions also involve some sort of energy change. (Energy is the ______.)  If energy is given off in a chemical reaction (often as heat), the reaction is classified as ______. Your body undergoes exothermic reactions when it breaks down sugars to release heat and energy.  If energy is absorbed in a chemical reaction (an input of energy is needed), the reaction is classified as ______. Photosynthesis is an endothermic, requiring energy from sunlight to fuel the reaction.  Physical changes refer to changes in a substance's physical properties without ______. When water freezes a physical change takes place. But water is water </p><p>(H2O) whether solid (ice), liquid, or gas (steam).</p><p>Obj 1.6 Describe the 3 main states of matter and the terms used to describe the temperatures at which matter changes physical states (problems p 46 #20, 30, 31, 34)</p><p>Matter is either ______, ______, or ______. (A fourth state, plasma, will be discussed in another unit.)  Each substance has unique freezing/melting and boiling/condensation temperatures, which can be useful for identifying and separating substances.  When a solid heats up to certain temperature (its ______) it will change to a liquid state. When a liquid cools to a certain temperature (its ______) it will change to a solid state.  When a liquid heats up to a certain temperature (its ______) it will change to a gaseous state. When a gas cools to a certain temperature (its ______) it will change to a liquid state.  A substance's melting and freezing points are usually the same temperature, and its boiling and condensation points are also usually the same temperature. </p>