Enthalpy change - Study guides, Class notes & Summaries

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...

Exam 1 Correct Answer- A reaction consists of a reactant "R" being converted into a product "P". The change in enthalpy of the conversion is 5 kJ/mol, while the change in entropy is 35 kJ/mol. Therefore, thermodynamic coupling is not required for this reaction to reach an equilibrium. True/False Correct Answer-True Which of the following is true regarding a reaction that has a ΔG° = 0. The concentrations of the reactants and products are equal. The reaction will eventually arriv...

BioChem 210 Module 2 Exam - Portage Learning 1. The pH of a solution of 0.0010 M NaOH is:: 11 (Kw=[H+][OH-] = 1.0 x 10-14; [H+][0.0010] = 1.0 x 10-14 [H+]=1.0 x 10-11; pH=-log[1.0 x 10- 11]=11) 2. Water is a unique molecule. Which of the following contributes to water's unique place in the chemical world?: All of the answers are correct 3. The bent shape of water is due to ______________.: The unshared electron pairs on the oxygen atom 4. Which diagrams correctly represent ...

IB chemistry HL Latest Version Graded A+ exothermic reaction heat is released by the system ΔΗ<0 endothermic reaction heat is absorbed by the system ΔΗ>0 standard enthalpy change of reaction(ΔΗ) the heat energy transferred under standard conditions (pressure-101.3 kPa, temperature- 298 K) combustion and neutralization are exothermic processes average bond enthalpy the energy required to break one mole of a certain type of bond in the gaseous state averaged acro...

15 kg/s of air are compressed from 1 atm and 300K (enthalpy of 300.19 kJ/kg) to 2 atm and 900K (enthalpy of 732.93 kJ/kg). Heat transfer is negligible. The air compressor's power output is most nearly (A) 5.6 MW (B) 6.5 MW (C) 7.6 MW (D) 8.9 MW - Answer-B What is most nearly the weight in lbf if a 1.00lbm object in a gravitational field of 27.5ft/s^2? (A) 0.85lbf (B) 1.2lbf (C) 28lbf (D) 32lbf - Answer-A A rocket that has a mass of 4000 lbm travels at 27,000 ft/sec. What is mo...

What is the third law of thermodynamics? Correct Answer The entropy of a perfect crystal is zero. What is the second law of thermodynamics? Correct Answer As a whole, the universe always tends towards increasing entropy. What is the relationship between number of microstates and entropy? Correct Answer More microstates = higher entropy What is the relationship between temperature and entropy? Correct Answer Temperature increases, entropy increases (direct) What is the relationship be...

IB Chemistry Topic 5 Latest Update Graded A+ Enthalpy The amount of heat released (exothermic) or absorbed (endothermic) during a chemical reaction (the energy needed for the reaction to occur) This can be lowered with the presence of a catalyst. Change in Enthalpy Hproducts -Hreactants Specific heat equation c= q in Joules (or Change in H)/mass(g)(change in temp) Specific heat of water 4.18 J/gdegreesC **NOTE: Usually in kJ Endothermic v. Exothermic Endothermic: Absorbing e...

Chem Exam: Types of Calculation Questions & Answers 100% Verified Calorimetry Calculations: 1. 2.50 kJ of energy changes the temperature of a sample of lead by 8.52 degrees C. What is the mass of the sample? - ANS-Q = mcΔT m=Qc/Δt m = 2500/0.13(8.52) = 2.3×103 g 2. 950.3 J of energy is removed from 28.5 g of water at 80.3 degrees C. What is the final temperature? - ANS-Q = mcΔT −950.3 = 28.5(4.18)(T2 − 80.3) T2 = −950.3/(28.5)(4.18) + 80.3 = 72.3O C 3. A 30.56 g sample...

CEM 142 EXAM 2 LATEST UPDATE GRADED A+ **ACID = ELECTRON PAIR ACCEPTOR Acid= electrophile **BASE = ELECTRON PAIR DONOR base= nucleophile strong acid fully ionizes in solution/completely dissociates weak acid does not fully ionize or dissociate into ions ** negatively charged ion ---> wants to loose 1 electron can tell if a solution is ionized when... a fully ionized solution will conduct more electricity than a non fully ionized solution strength of acid depend...

elative atomic mass (Ar) : Average mass of an atom compared with one twelth of the mass of an atom of carbon 12 Electronegativity : Power of an atom to attract the pair of electrons in a covalent bond Standard enthalpy of combustion : Enthalpy change when 1 mole of a substance burns completely in oxygen under standard conditions with all reactants and products being in their standard state Standard enthalpy of formation : Enthalpy change when 1 mole of a compound is formed from it's ...