Conservation of Mass Study Guide

Conservation of Mass Study Guide Name: _____________________

DEFINITION	EXAMPLE 1 (in class)		EXAMPLE 2		EXAMPLE 3
Law of Conservation of Mass states matter cannot be ___________ or ____________, only change form. This means the mass of the _____________ in a chemical reaction must equal the mass of the ________________.	10 grams of Sodium + 20 grams of Chlorine à _______ grams of Sodium Chloride OR 15 g of Hydrogen + ______ g of Oxygenà 18 g of Dihydrogen Oxide (water)		________g of hydrogen + 2 g of Chlorine à 18 g of Hydrogen Chloride OR 21 g of Zinc + 5 g of Sulfur à _________ g of Zinc Sulfide		Your own example:
A chemical reaction is any change which ____________ the chemical properties of a substance or which forms a __________________. It is the exchange of _____________ in the outer shell. Evidence of chemical reactions or chemical change is a change in ___________, _____________, burning, adding heat, the formation of a _________ (powder) or a _________ (see your notes). It is difficult or impossible to change substances in a chemical reaction back to _____________ form. Chemical reactions form compounds.	Na + Cl à NaCl Sodium + Chlorine à salt		(See pg. 209 and the periodic table). You may use both ionic and covalent bonds. Make at least two chemical reactions.		(See pg. 209 and the periodic table) You may use both ionic and covalent bonds. Make at least two chemical reactions.
The elements and chemicals to start a chemical reaction are the _____________. The substances that are formed during the reaction (or what we end with) are the ____________.	Reactants Na + Clà H2 + Oà	Products NaCl (salt) H2O (water)	Reactants K + Cl à __ + __à Ca + Cl2à	Products FeI3 _________	Reactants: your own examples	Products:
Almost every chemical reaction involves a change in ___________. Exothermic reactions produce ________. Think of “exo” as heat exiting the substance so we can feel it. Thermic means heat. Think of “thermos”. In exothermic reactions the temperature _________.	Example: Burning wood		Your own example:		Your own example:
Endothermic reactions are reactions that _________or require heat. “En” means the reaction will take energy in and use it up in the reaction. In endothermic reactions the temperature ____________ because the heat is used up in the chemical reaction.	Example: baking soda and vinegar		Your own example:		Your own example:
Ionic bonds form when an atom _________ or __________ electrons. It happens between a ___________ and non-metal. Ionic bonds produce __________ or positive and negative charges.	Na + Cl à NaCl Metal + non metal Na + Cl à Na Cl Picture:		(Include formula and picture)		(Include formula and picture)
Covalent bonds form when an atom __________ electrons. It happens between a _____________ and a non-metal. It does not produce _________.	H2 + O à H2O Non-metal + non-metal Picture (Lewis Dot Diagram):		Include formula and Lewis Dot Diagram.		Include formula and Lewis Dot Diagram.
Ions are __________ and _____________ charges formed by ionic compounds. Electrons have a _____________ charge. When Na (sodium) loses electron it becomes ___________. When Cl (Chlorine) gains an electron it becomes ____________.	Na + Cl à Na Cl		Choose a metal and non metal and show positive and negative charges.		Choose a metal and non metal and show positive and negative charges.
Oxidation number is the number of electrons an atom is capable of _____________, _____________ or sharing. (pg 301-302)	Calcium has an oxidation number of 2. This means it tends to lose two electrons, thus becoming positively charged. Ca²		Find the oxidation number and put the charge: H (hydrogen): ______ O (oxygen): ________ Si (silicon): _________ C (carbon): _________		Find the oxidation number and put the charge: Cl (Chlorine): ____ K (Potassium): ___ N (Nitrogen): _____ P (Phosphorus): ­­___
A subscript shows the number of ________ an element in a chemical reaction. A way to remember subscript is to remember “sub” which means ___________(pg. 301, 306)	Ca + Cl2 à CaCl2		Find the missing subscripts to balance the chemical equation/reaction. Fe2 + S à Fe__S Fe + I3 à Fe + I__ Cr + PO4 à CrPO__		Find the missing subscripts to balance the chemical equation/ reaction. Si + O2à O__ +Si HF4+ SiO2à SiF__ +HO__
A coefficient is a number written before the element symbol to ___________ an equation. It acts as a ___________ for the atom or molecule. One must___________ the equation because the Law of Conservation of Mass states the mass of the reactants must equal the mass of the __________.	Fe + 2HClà FeCl2 + H2 This means there are two hydrogen and two _____ on the reactant side and ______ Chlorine and _______ Hydrogen on the product side of an equation. (pg. 305-306) *Think of algebra equations for similar rules.		Find the missing coefficient to balance the equations/ reactions: ___K + SO4 à K3SO4 ___Li + Br2 à ___LiBr ___As+__NaOà As2+Na3O3 Au6 + ___Sà __Au +S4		Find the missing coefficient to balance the equations/ reactions: 2N2 +5O2 à __O+__N __HCl+ Znà ZnCl2+ H2
Binary compounds are made of ______ elements. “Bi” means _________. Think of bicycle. (Pg. 302)	Fe + S à FeS		Your own example:		Your own example:
Polyatomic ions are groups of atoms that act ___________ as a single charged atom or group. “Poly” means more than _______. It is like a group or gang of atoms with the same charge. (Pg. 303)	Iron (III) or F³ Nitrate NO³		Your own example:		Your own example:
Organic compounds are compounds containing ____________. They may be __________ or non-living. Over _____% of all known compounds contain carbon. 1st organic compound: Hydrocarbons contain ___________ and ____________. 2nd : Polymers are made synthetically (in the lab) from ______________. 3rd: Alcohols are composed of ________, ________and ________. 4th: Fats, carbohydrates, proteins, and vitamins.	*Note the word organic in chemistry is not the same as organic farming! Hydrocarbons: fossil fuels such as methane: CH4 Polymers: are often plastics. Alcohols: propyl alcohol CH3CH2Ch2OH Protein: butyric fat in milk is CH3(CH2)2COOH but there are 11 more types of fat in milk + H20 and lactose		Put an example of each type of organic compound. Hydrocarbon: Polymer: Alcohols: Protein/fat/carbohydrate or vitamin:		Put an example of each type of organic compound. Hydrocarbon: Polymer: Alcohols: Protein/fat/carbohydrate or vitamin:
Valence electrons are electrons in the ________ electron shell of an element. An element needs ______ electrons or an octet to be _________ or not want to chemically react with another element.	Valence electrons of Helium: 8 so it is stable. *See the number at the top of the column, not the atomic number (this is the total number of protons or electrons it has, not the valence electrons).		Valence electrons of Sodium: _____ Calcium: _____ Oxygen: _____ Nitrogen: _____		Valence electrons of: Silicon: _______ Hydrogen: ______ Gold: ________ Mercury: ________