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Chemistry: Unit #3
Chem 1015 Exam 3
| Question | Answer |
|---|---|
| Kinetic Molecular Theory | Predicts the correct behavior for most gases under many conditions. |
| The Kinetic Molecular Theory makes the following assumptions: | 1. Gas is a collection of particles in constant, straight lined motion. 2. Gas particles do not attract or repel each other- they do not interact. 3. There is a lot of space b/t gas particles. 4. As temp. inc., particles move faster and have more energ |
| Properties of gases | Are compressible, assume the shape and volume of their container, and have low densities in comparison w/ liquids and solids. |
| What is pressure? | Pressure is the result of the constant collisions b/t the atoms of molecules in a gas and the surfaces around them. Pressure = Force / Area |
| Boyle's Law | The volume of a gas and its pressure are inversely proportional. P1 V1 = P2 V2 |
| Charles's Law | The volume of a gas and its Kelvin temperature are directly proportional. V1/T1 = V2/T2 |
| Combined Gas Law | Used for a sample of gases under two different sets of conditions. P1V1/T1 = P2V2/T2 |
| Avogadro's Law | The volume of a gas and the amount of the gas in moles (n) are directly proportional. V1/n1 = V2/n2 |
| The Ideal Gas Law | Pressure, volume, temperature, and moles. PV = nRT (where R is constant .0821 L.atm/mol.K |
| Molar Mass | Mass (m)/Moles (n) |
| Dalton's Law of Partial Pressures | Ptot = Pa + Pb + Pc + ... |
| In standard pressure conditions, what is the volume of 1 mol? | 1 mol : 22.4 L |
| What is stoichiometry? | Numerical relationship b/t chemical quantities in a balanced chemical equation. |
| Mass-to-Mass Conversions | Mass A --> Moles A --> Moles B --> Mass B |
| What is the limiting reactant? | The reactant that makes the least amount of product. The reactant is completely consumed in a reaction. |
| What is the theoretical yield? | The amount of product that can be made in a chemical reaction based on the amount of limiting reactant. |
| What is the actual yield? | The amount of product actually produced by a chemical reaction. |
| How do you determine the percent yield? | Actual yield/Theoretical yield x 100% |
| What is the enthalpy of reaction? | The amount of thermal energy that flows when a reaction occurs at constant pressure. (delta H rxn) When this is negative, the reaction is exothermic. When this is positive, the reaction is endothermic. |
| What do you do when solving stoichiometry involving delta H? | You use the solution map: g --> mol --> kJ |
| What is a chemical reaction? | The transformation of one or more substances into different substances. |
| What are gas evolution reactions? | Reactions that occur in liquids and form a gas. |
| What are combustion reactions? | In which a substance reacts with oxygen, emitting heat, and forming one or more oxygen-containing compounds. |
| What are oxidation-reduction reactions? | In which electrons are transferred from one substance to another. |
| What are precipitation reactions? | Form solid substances in water. |
| Evidence of a chemical reaction | Color changes, formation of a solid, formation of a gas, heat absorption/emission, or light emission. |
| What are the reactants in a chemical equation? | The substances on the left side of the equation. |
| What are the products in a chemical reaction? | The substances on the right side of the equation. |
| What makes an equation balanced? | Numbers of each type of atom on both sides of the equation are equal. |
| What is an aqueous solution? | A homogeneous mixture of a substance with water. |
| What makes a compound soluble? | If in a particular liquid it dissolves in that liquid it is soluble. |
| What is the key to predicting precipitation reactions? | Understanding that only insoluble compounds form precipitates. |