Matter & Change Chapter 1 Pages 3 - 20

Chemistry is a Physical Science The physical sciences focus on ________________. Why is chemistry central to all the sciences? Chemistry is defined as: ______  What two questions do chemists answer through work in the lab? How many branches of chemistry are listed in your text book? List these branches. Which of these branches do you think is most important to human society as you know it to be today? Why do you think this branch is most important?

Chemistry is a Physical Science

Chemistry is a Physical Science A chemical is any substance that has a definite composition. Definite composition means that a chemical has the same number of atoms for one molecule of a substance. Water is H2O. Water is a chemical. One molecule of water has exactly 2 atoms of hydrogen and one atom of oxygen per molecule of substance.

Matter & its Properties What is volume? Mass is a measure of the amount of ________ a substance has. What is matter? What are the 2 fundamental building blocks of matter? An atom is the smallest unit of a(n) __________ that maintains the chemical identity of that _________. __ ____________ is a pure substance that cannot be broken down into simpler, stable substances and is made of one type of atom. Can a compound be broken down into simpler substances? Compounds are made of atoms of two ore more elements that are ______________________.

Matter & its Properties

Matter & its Properties Comparisons of several properties of an unknown substance can be used to establish its identity. Properties can be extensive or intensive. EXTENSIVE PROPERTIES include: Volume Mass Energy quantity Defined: depend on the amount of matter present. A chemistry student takes a sample of substance to a digital scale in the lab. Her sample is found to weigh 2.56 g. Which extensive property does her measurement represent? Another student has a solid block of substance and measures its length, width and height with a ruler using centimeters (cm). Next he multiplies these three measurements for a product of 4.56 cm3. Which extensive property does his measurement represent?

Matter & its Properties INTENSIVE PROPERTIES include: Melting point Boiling point Density Conductivity ((?)) Defined: do not depend on the amount of matter present. They are the same for a given substance regardless of how much substance is present. Another chemistry student tests the melting point of 2.45 g of a solid substance and compares its melting point to 5.67 g of the same solid substance. Will they have the same melting points? Next, she measures heat conductivity of both substances of varying masses. Will they have the same amount of conductivity?

Matter & its Properties Physical properties can be observed/measured _________ changing the identity of substance. A physical change occurs when the ________ of the substance is not changed. Chemical properties are a substance’s ability to undergo changes that _________ it into different substances. A chemical change (chemical reaction) is when one or more substances are __________ into different substances. Solids have definite _______ & _________. What is an example? Liquids have definite volume but no definite ________ because they take the shape of their containers. What is an example? Gases have no definite _______ or ________. What is an example? Liquids and gases, because they take the shape of their containers are known as _________.

Matter & its Properties Substances that react in a chemical change are called reactants. HCl + NaOH  NaCl + H2O Substances that are formed by the chemical change are called products. Energy is always involved when physical or chemical changes occur. Consider ice melting. What type of change of state has occurred? (physical or chemical). When wood burns to ash, what type of change of state has occurred? (physical or chemical). What do both of these changes have in common?

Matter & its Properties

Elements …are pure substances that cannot be decomposed by _______________. The periodic table is an organization of ___________. Vertical columns of the periodic table are called _______. (they are also called families but we will refer to them as the answer for your blank). Horizontal rows on the table are called ________. Metals have what 3 properties listed by your textbook? The ability to be hammered or rolled into sheets is called _____________. The ability to be drawn into thin wire is called __________. The ability to resist breaking when pulled is called __________. Most metals are solid at room temperature. What is an example of a metal that is NOT solid at room temperature? Why is this unique physical property important to us?

Elements

Elements Most nonmetals are gases at room temperature: N, O, F and Cl. Others are solid at room temperature: C, P, Se, S & I. Br (bromine) is liquid at room temperature. Metalloids have properties of both metals and non metals. They are ALL solid at room temperature. They are semiconductors of electricity which makes them useful in current technological devices such as computers, digital watches and radios.

Elements What do you know about noble gases? Do they have a full outer electron shell? Do they have a filled or “satisfied” octet? Are they reactive with other elements? Why or why not? Can you identify the noble gases on a periodic table? What is your favorite noble gas? Why is this your favorite noble gas? What is the group number for the noble gases? What is another name for “noble gas”?