Intro to Chemistry Exam 3 Questions and Answers.
Covalent compound - ANS They exist as molecules and can not be broken down by
physical means. If melted or dissolved in water they do not conduct electricity.
Properties of a covalent compound - ANS Can be gas liquid or solid at room temperature.
Covalent bond - ANS Electrons are shared in this type of bond. One, two, or three
electrons are shared to attain the Noble Gas structure.
Mole - ANS They turn AMUs to grams. They make atoms measurable.
C-12 (Carbon 12) - ANS All atoms are compared to __________.
12 grams - ANS 1 mole has a mass of ___________.
Molar mass - ANS The total mass of all the atoms in a compound.
Chemical equations - ANS A universal short hand way to explain what happens in a
chemical reaction. They are balanced so their equal numbers of each type of element on
each side of the equation.
The law of conservation of mass - ANS What law do chemical equations follow?
Reactant - ANS What you start with in a chemical equation
Products - ANS What you end up with in a chemical equation
Coefficiants - ANS Balance the reaction so their equal number of each type of atom on
each side of the equation.
Combination - ANS Two or more reactant forms two or more products. Example
2Na+Cl2------> 2NaCl
Decomposition - ANS One reactant forms two or more products. Example CaCo3 ------>
CaO+CO2
, Combustion - ANS A material containing carbon and hydron reacts with oxygen to
produce CO2 + H2O plus lots of energy.
Single replacement - ANS One atom replaces another in a reaction. Example
Na(s)+Ag(NO3)(aq)------> Ag(s)+Na(NO3) (aq)
Limiting reagent - ANS The reactant that runs out controls how much is produced and is
called _____.
Enthalpy - ANS The energy store in bonds.
Increases enthalpy - ANS In an endothermic reaction more energy is needed to break
bonds then is given off forming bonds and the change is positive. What happens to the
enthalpy?
Decreases enthalpy - ANS In an exothermic reaction more energy is given off forming
bonds than is needed to break the bonds, change is negative. What happens to the
enthalpy?
Endothermic reaction - ANS Energy is absorbed
Exothermic reaction - ANS Energy is released
Possitive - ANS In an endothermic reaction change is________.
Negative - ANS In an exothermic reaction change is_________.
Photosynthesis - ANS What is an example of an endothermic reaction?
Burning methane - ANS What is an example of an exothermic reaction?
Bonds are broken or loosened - ANS What happens to the bonds during an endothermic
reaction?
Bonds are formed or tightened - ANS What happens to the bonds during an exothermic
reaction?
Covalent compound - ANS They exist as molecules and can not be broken down by
physical means. If melted or dissolved in water they do not conduct electricity.
Properties of a covalent compound - ANS Can be gas liquid or solid at room temperature.
Covalent bond - ANS Electrons are shared in this type of bond. One, two, or three
electrons are shared to attain the Noble Gas structure.
Mole - ANS They turn AMUs to grams. They make atoms measurable.
C-12 (Carbon 12) - ANS All atoms are compared to __________.
12 grams - ANS 1 mole has a mass of ___________.
Molar mass - ANS The total mass of all the atoms in a compound.
Chemical equations - ANS A universal short hand way to explain what happens in a
chemical reaction. They are balanced so their equal numbers of each type of element on
each side of the equation.
The law of conservation of mass - ANS What law do chemical equations follow?
Reactant - ANS What you start with in a chemical equation
Products - ANS What you end up with in a chemical equation
Coefficiants - ANS Balance the reaction so their equal number of each type of atom on
each side of the equation.
Combination - ANS Two or more reactant forms two or more products. Example
2Na+Cl2------> 2NaCl
Decomposition - ANS One reactant forms two or more products. Example CaCo3 ------>
CaO+CO2
, Combustion - ANS A material containing carbon and hydron reacts with oxygen to
produce CO2 + H2O plus lots of energy.
Single replacement - ANS One atom replaces another in a reaction. Example
Na(s)+Ag(NO3)(aq)------> Ag(s)+Na(NO3) (aq)
Limiting reagent - ANS The reactant that runs out controls how much is produced and is
called _____.
Enthalpy - ANS The energy store in bonds.
Increases enthalpy - ANS In an endothermic reaction more energy is needed to break
bonds then is given off forming bonds and the change is positive. What happens to the
enthalpy?
Decreases enthalpy - ANS In an exothermic reaction more energy is given off forming
bonds than is needed to break the bonds, change is negative. What happens to the
enthalpy?
Endothermic reaction - ANS Energy is absorbed
Exothermic reaction - ANS Energy is released
Possitive - ANS In an endothermic reaction change is________.
Negative - ANS In an exothermic reaction change is_________.
Photosynthesis - ANS What is an example of an endothermic reaction?
Burning methane - ANS What is an example of an exothermic reaction?
Bonds are broken or loosened - ANS What happens to the bonds during an endothermic
reaction?
Bonds are formed or tightened - ANS What happens to the bonds during an exothermic
reaction?
