Enthalpy change - Study guides, Class notes & Summaries

CHEM 210 MODULE 3 EXAM QUESTIONS AND CORRECT ANSWERS, WITH COMPLETE SOLUTION 2024. What is meant by the term average bond enthalpy? (Average enthalpy change) when one mole of bonds of (gaseous covalent) bonds is broken The calculated value of ΔHc from this experiment is different from the value obtained from data books. Apart from heat loss, suggest two reasons for the difference. Assume that the calculation has been carried out correctly. incomplete combustion non-standard conditi...

Lattice energy - - The enthalpy change when 1 mole of ionic compound is formed from its gaseous ions under standard conditions - It is the energy given out when ions of opposite charges comes together to form an ionic lattice Lattice energy is endothermic or exothermic? - - It is always exothermic because bonds are being formed (ionic bond) between oppositely charged ions, not broken Equation showing the formation of NaCl lattice - - Na^+(g) + Cl^-(g) > NaCl(s) The state of the opposite...

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

AQA A-Level Chemistry Exam (2024) || All Questions & Answers (Graded A+) AQA A-Level Chemistry Exam (2024) || All Questions & Answers (Graded A+) Topic 1 - ANSWER - Atomic Structure Topic 2 - ANSWER - Amount of Substance State what is meant by the term molecular formula. - ANSWER - the actual no. atoms of each element in a compound Topic 3 - ANSWER - Bonding Explain why CF4 has a bond angle of 109.5°. - ANSWER - -there are 4 bonding pairs and no lone pairs -repel equally and th...

AQA CHEMISTRY A LEVEL WITH COMPLETE SOLUTIONS covalent bond - ANSWER-a shared pair of electrons between non-metal elements co-ordinate bond - ANSWER-a shared pair of electrons where both electrons are supplied by one atom repulsion in shapes of molecules - ANSWER-Lone pair-lone pair > lone pair-bonding pair > bonding pair-bonding pair electronegativity - ANSWER-the power of an atom to attract the pair of electrons in a covalent bond hess' law - ANSWER-Total enthalpy chang...

Chem 142 Unit 1 Latest Update Graded A+ Thermodynamics The study of energy and its transformation Thermochemistry The study of chemical reactions and transformations and the energy changes that accompany these transformations Electrostatic Potential Energy Equation - k = constant - Q = the 2 charges (Eel is negative if the charges are opposite and positive if the charges are like) - d = distance between the two particles Potential Energy for like charges Repulsion; Positive;...

Honors Chemistry Final Exam Questions and Answers 100% Pass What is the term for the energy required to change a substance from a liquid to a solid at its freezing point? Heat of Fusion What is the name of the process in which a gas turns directly into a solid? Deposition What is the term for the property of a solution that describes the maximum amount of solute that can dissolve at a given temperature? Solubility What is the name of the type of bond formed when electrons ...

temperature is related to KE how? temp is the average kinetic energy thermal energy is related to KE how? thermal energy is the total KE Brainpower enthalpy of fusion is ALWAYS greater than enthalpy of vaporization because? it has to break more bonds (solid --> liquid) the amount of heat depends on (2 factors) 1. the type of substance 2. the amount of the substance during a phase change does temperature change? NO if an archaebacerial species lives in a pool that is 0.01 M HCL wh...

CEM 142 First Exam Latest Update Already Passed Define and give examples of open, closed and isolated systems Open system-both matter and energy can enter or leave (beaker without a lid, pour your hot drink into a mug) Closed system- the amount of matter is constant and only energy can enter or leave (cup of coffee with a lid on it) Isolated systems- neither energy nor matter would move between the system and the surroundings (Styrofoam coffee cup with a lid on) Explain the dif...

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...