# Term 3 – Chemistry

Flashcard maker : Darryl Wooten
 What are the two types of energy and why are they unique?
 kinetic energy or energy that is in motion potential energy or stored energy
 How is heat measured?
 Heat, q, is measured in calories and in a hot to cold flow
 What is a calorie?
 A calorie is the amount of energy needed to raise to raise the temperature of 1g of water 1°C
 What is specific heat and what is the formula?
 Specific heat is the amount of energy that it takes to raise any substances temperature 1°C, with the formula being q=mCΔT, where m is mass measured in grams
 When is energy exothermic?
 Energy is exothermic when heat is released, it feels hot, and there is a negative sign
 When is energy endothermic?
 Energy is endothermic when energy is absorbed, it feels cold, and it is a positive sign
 What is fusion and what is its ΔH?
 Fusion is melting and has a ΔH of 6.01kJ/mol
 What is vaporization and what is its ΔH?
 Vaporization is changing a liquid to a gas and its ΔH is 40.7 kJ/mol
 What is Hess’s Law or calculating Enthalpy?
 Hess’s Law is the total enthalpy in a system is equal to the sum of the steps of the reaction.  It is a way to calculate the change in enthalpy.  The key to this is when you flip be sure to flip the sign of the ΔH as well.
 What is spontaneity?
 Something which occurs without outside intervention
 What is entropy?
 Entropy is a factor that helps determine if something will be spontaneous.
 What is ΔS?
 This is the molecular randomness or disorder.  When it is positive, there is more disorder, and when it is negative, there is less order.
 How do you predict changes in spontaneity?
 1. Changes in state *s -> l ΔS = + *g -> l ΔS = – 2. Dissolving gas *ΔS = – 3. Increasing the number of gas particles *ΔS = + 4. Dissolving solid *ΔS = + 5. Increasing temperature *ΔS = +
 What is free energy and what is its formula?
 Free energy is whether or not something is spontaneous ΔG = ΔH – TΔS
 What is equilibrium?
 Equilibrium is a state of dynamic balance
 What does it mean to be far right or far left and what color is each of these?
 To be far right means you have more products and is generally a lighter color.  To be far left means you have more reactants and is generally a darker color
 What is dynamic balance?
 Dynamic Balance is where there is no change that is apparent with the motion of the reaction because of the change in rate.
 What is the equilibrium’s constant and expression?
 jA + kB ;-; lC + mD K=[C]l[D]m/[A]j[B]k
 What happens with constants for homogeneous equilibria and heterogeneous equilibria?
 Homogeneous equilibria is when all reactants and products are in the same physical state. ;Heterogeneous equilibria is when you should only include liquids and aqueous solutions into the expression.
 When determining the value of an equilibrium constant how do you know which way the equation goes?
 Greater than 1 is to the right Less that 1 is to the left 1 is equal equilibrium
 What is Le Chatelier’s Principle and how do you determine the left and right arrows?
 Le Chatelier’s Principle is about disturbing equilibrium and stress that upsets a system at the equilibrium. ;You determine which way the left and right arrow should point by allowing it to be in the direction of the up arrows.
 What are the steps to finding solubility?
 1. Write the equation 2. Write the Ksp;expression 3. Make all [] into x’s 4. Fill in the Ksp value using the table
 What is Ksp and what is it used for?
 This is the equation that is used to find the solubility of an ionic compound in water at room temperature
 What is enthalpy?
 Enthalpy is the heat content of a system at constant pressure, the amount capable of doing mechanical work
 What is the definition of free energy?
 Free energy is a system that is available to do work
 What do the Gas Laws work with and what should be assumed?
 ideal gases 1. particles have zero volume (they take up no space) 2. there is no attractive force (they don’t stick)
 What is Boyle’s Law?
 When temperature and n (moles) are constant Pressure and Volume are inversly related
 What is the formula for Boyle’s Law?
 P1*V1 = P2*V2
 What does the graph need to be for Boyle’s Law in order to get a positive slope?
 Pressure vs. 1/V
 What is Charles’ Law?
 When Pressure and n (moles) are constant Temperature and Volume are directly related
 What is the formula for Charles’ Law?
 V1/T1 = V2/T2
 What is the graph for Charles’ Law?
 Volume vs. Temperature
 What is the lowest possible temperature?
 -273;C or 0;K
 How do you convert Celsius into Kelvin?
 K=;C + 273
 What is John’s Law and what is another name for it?
 Pressure and Temperature are directly related Gay-Lussac
 What is the formula for John’s Law?
 P1/T1 = P2/T2
 What is the graph for John’s Law?
 Pressure vs. Temperature
 Pressure and the number of moles are directly related when volume and temperature are constant
 What is the formula for Avagadro’s Law?
 P/n = k
 What is the Combined Gas Law formula?
 P1V1/T1 = P2V2/T2
 What is the Idea Gas Equation?
 PV = nRT L*atm/mol*K
 What is the value of the constant R?
 R = .0821
 What are the formulas of molar mass determination and density?
 M = mRT/PV m = MPV/RT d = PM/RT
 What is a mixture?
 2 or more things put together
 What is a heterogeneous mixture?
 if when you look at a mixture and see the different elements
 What is a homogenous mixture?
 if when you look at a mixture and cannot tell the different aspects
 What is a solution?
 a mixture that looks the same throughout
 What is a solvent?
 the component in a solution that is in greater quantity
 What is the solute?
 the component that is in lesser amount
 When you classify a mixture does the solvent or solute come first?
 solvent
 How does energy form in a solid?
 solvation/hydration
 What are energy groups in a solution?
 polar-polar nonpolar-nonpolar polar-nonpolar
 Does the solvent or solute come first when classifying energy?
 solvent like dissolves like
 How does Temperature effect solubility?
 When there is an increase in speed more collisions are produced, the higher the temperature the more this happens ***gas is slower at a lower temperature
 What is Henry’s Law?
 a direct relation to Pressure and solubility the larger the particle is the harder it is to stir
 What is the formula for percent by mass?
 mass of solute/mass of solution * 100
 What is the formula for percent by volume?
 volume of solute/volume of solution * 100
 What is the formula for molarity?
 moles of solute/liters of solution
 What is the formula for a dilution of a solution?
 M1 * V1 = M2 * V2
 What is the formula for molality?
 m = moles of solute/kg of solvent
 What is the formula of a mole fraction?
 x = Mole A / Mole A + B
 What is a Colligative Property?
 a property of a solution dependent on the concentration of the solute
 What is the Vapor Pressure of a solution?
 water in the gas phase that can hang out right above the solution
 When does vapor pressure decrease?
 when you add a solute to a solvent;
 What is the formula for Vapor Pressure?
 Psolution;= Xsolvent;(VPsolvent) *******X stands for mole fraction
 What is the formula for boiling point?
 ;Tb;= Kbmsolutei
 ;Tf;= Kfmsolutei
 What is i in the freezing and boiling formulas?
 i is the number of pieces 1 for nonmetals metals and nonmetals however many
 What does saturate mean?
 a solution that contains as much dissolved solute as possible in the presence of undissolved solute
 What does unsaturated mean?
 anything below the amount of dissolved solute
 What does supersaturated mean?
 when more solute is dissolved than the solvent typically allows
 What are the properties of an acid?
 the formula begins with H it tastes sour reacts with metals to yield CO2;or H2O turns litmus paper pink pH is less than 7 ;
 What are the properties of a base?
 formula usually has OH- or NHx it tastes bitter it feels slippery turns litmus paper blue pH is greater than 7 used in cleaning products
 What is an Arrehnius model?
 an acid is a substance with hydrogen that will produce H+ in an aqueous solution a base is a substance with hydroxide that produces OH- in an aqueous solution
 What is a Bronsted-Lowry model?
 anything that donates a H+ is an acid anything that accepts a H+ is a base
 What is the formula for pH?
 -log(H3O)
 What is the formula for pOH?
 -log(OH–)
 How do you find pH from pOH?
 14-pOH