Enthalpy change - Study guides, Class notes & Summaries

Honors Chemistry Unit 4 Test Questions and Answers 100% Pass What is the term for the amount of energy released or absorbed during the formation of one mole of a compound from its elements in their standard states? Standard Enthalpy of Formation What is the name of the process in which a substance dissolves in a solvent to form a homogeneous mixture? Dissolution What is the term for the bond angle in a molecule with a tetrahedral geometry? 109.5 Degrees What is the name of...

What is the most important thing change in Gibbs free energy tells us? What does a negative value mean and what does a positive value mean? - how spontaneous a reaction is negative delta G = spontaneous, energy is released, exergonic positive delta G = non-spontaneous, energy is consumed, endergonic what does enthalpy represent? what does it mean when it's positive vs negative? - delta H is change in enthalpy, which is the heat content of the reacting system. It reflects the number and ...

10th Grade Honors Chemistry Final Exam Flashcards Thermochemistry ️The study of heat effects in chemical reactions. Exothermic Reaction ️A reaction that releases energy in the form of heat. Examples: Combustion, freezing water. Heat generated is added to the product side (right side) because heat is released. Endothermic Reaction ️A reaction that absorbs energy in the form of heat. Examples: Melting ice, evaporating liquid water, boiling water. Heat generated is added to the ...

Standard enthalpy of formation ֎ -:- The enthalpy change when one mole of a compound is formed from its elements under standard conditions, with all substances in their standard states. Standard change of atomisation ֎ -:- The enthalpy change when one mole of gaseous atoms is formed from the element in its standard state under standard conditions. First ionisation energy ֎ -:- The enthalpy change needed to remove one electron from each atom in one mole of gaseous atoms to form on...

Relative atomic mass : The average mass of an atom of an element, relative to 1/12th of the mass of an atom of Carbon-12 Relative molecular mass : Average mass of a molecule compared to 1/12th of the mass of a carbon-12 atom The Avogradro constant : the number of particles in a mole ideal gas equation : pV = nRT empirical formula : the simplest whole number ratio of atoms of each element in a compound 2 percentage atom economy : (Mass of desired product/total mass of reactants) x 1...

rate of reaction ֎ -:- the change in concentration of a reactant or product per unit time rate constant (k) ֎ -:- The constant that links the rate of reaction with the concentrations of the reactants raised to the powers of their orders in the rate equation. half-life ֎ -:- The time taken for the concentration of the reactant to reduce by half Benzene ֎ -:- a naturally occurring aromatic compound, which is a very stable planar ring structure with delocalised electrons Model ֎ -...

Phase - Answer-Substance in a form of matter which is homogeneous throughout in chemical composition and physical state Transition - Answer-A change from one state to another at a characteristic temperature and a given pressure What happens to free energy between phase in a spontaneous process? - Answer-The free energy decreases between phases What happens to free energy as the pressure increases? - Answer-Free energy increases as pressure increases due to the fact that molar volume is al...

A __________ ΔH corresponds to an __________ process. -zero, endothermic -positive, exothermic -negative, endothermic -zero, exothermic -positive, endothermic correct answerspositive, endothermic Which one of the following is NOT considered a fossil fuel? -natural gas -hydrogen -anthracite coal -petroleum -crude oil correct answershydrogen Which one of the following statements is FALSE? -The enthalpy change for a reaction is equal in magnitude, but opposite in si...

Lattice enthalpy The enthalpy change when one mole of an ionic compound is converted to gaseous ions. Enthalpy of atomisation The enthalpy change when one mole of gaseous atoms isformed from the element in its standard state. First electronaffinity The enthalpy change when one mole of gaseous atoms is converted into gaseous ions with a single negative charge. Enthalpy of solution The enthalpy change when one mole of a solute dissolves in water. Enthalpy of hydra...

Materials For this paper you must have: • the Periodic Table/Data Booklet, provided as an insert (enclosed) • a ruler with millimetre measurements • a scientific calculator, which you are expected to use where appropriate. Instructions • Use black ink or black ball-point pen. • Fill in the boxes at the top of this page. • Answer all questions. • You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. • If ...