Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Chemistry: Unit 1SJB
Chemistry: Phases in Detail & Heat/ Heat Equations
| Question | Answer |
|---|---|
| Phases in Detail: Gases | - molecules spread out and fill spaces they are given - weak intermolecular forces of attraction - large spaces between particles |
| Evaporation | takes place at all temperature on the liquid/ vapor boundary -increases with an increase in temperature |
| Vapor | definition: a gaseous phase of a substance that is a liquid or sold at normal conditions - once liquid particles have absorbed enough energy to overcome attractive forces, they become this |
| Vapor Pressure | gas particles exert pressure on the liquid when they evaporate - In closed system, pressure increases (ex: lid on top of boiling water; nothing in/out) -increases with an increase in temperature |
| Reference Table H #1 | -101.3 kPa= standard pressure (Table A) -1 atm, 760 turr, 760mmHg are values equivalent to Standard Pressure |
| Reference Table H #2 | -Normal boiling point: when the vapor pressure is equal to atmospheric pressure -When a substance boils, evaporation occurs throughout the liquid -Measures the strength of intermolecular forces between molecules -When a substance |
| Intermolecular forces between molecules | 1) If the vapor pressure is high- the attraction between molecules are weak (propanone) 2) If the vapor pressure is low- the attraction between molecules are strong (ethanoic acid) |
| 4 main types of energy | 1) Kinetic Energy (KE): Energy in Motion 2) Potential Energy (PE): Stored Energy 3) Chemical Energy (Energy assorted with a chemical change 4) Heat Energy |
| Heat Energy | Amount of energy transferred from one substance to another - can be measures using a calorimeter - calories (cal) or joules (J) measure heat gain or loss - to convert from cal to J to Kcal or KJ: divide by 1,000 |
| Law of Conservation of Energy | - energy is neither creates or destroyed 1. energy can be transferred from one substance to another 2. Or energy can be transferred into a new form of energy 3. the TOTAL AMOUNT OF ENERGY WILL REMAIN THE SAME |
| (Thermometry): Temperature | the measure of the average kinetic energy of the particles of a substance |
| (Thermometry): Heat | 1. flows spontaneously from a hot object to cold object ex: body heat to chair, boiling water to hand, burned hand to icepack |
| (Temperature Scales): Degrees Celcius (°C) | -most commonly used scale - temps below zero are negative -2 fixed points - 0°C: melting/ freezing point of water - 100°C: boiling/ condensation of water - values on a thermometer increase by 1°C |
| (Temperature Scales): Kelvin #1 | -contains theoretically the lowest possible temperature/ 0 Kelvin (absolute zero) - has never been exactly reached (1/1000 K) - Absence of all kinetic energy (no motion of particles) - scale is the same as Celcius, just shifted by 273 |
| (Temperature Scales): Kelvin #2 | -1 degree change in Celcius is the same as 1 degree change in Kelvin -Table T: K= °C + 273 |
| Thermometers | - device used to measure the average kinetic energy of particles and temp - uses liquids like Hg (Mercury) and colored alcohols that expand at high temperature |
| Measurement of Heat Energy | the amount of heat given off or absorbed in a reaction |
| (Table T): q=mc▲T #1 | q= heat (in Joules or calories) m= mass of substance (g) c= specific heat capacity of substance (J/g°C) ▲T= final temp-initial temp (in °C) |
| (Table T): q=mc▲T #2 | *ONLY USED when there is a CHANGE IN TEMP 1. the amount of heat needed to raise 1.0g of a substance by 1.0°C 2. the value for specific heat of water is on Table B |
| (Table T): Heat of Fusion | the amount of heat needed to MELT 1.0g of a substance *q=mHf is used when calculating how much heat is absorbed when a substance MELTS or FREEZES (Table B) **(NO CHANGE IN TEMPERATURE)** |
| (Table T): Heat of Vaporization | the amount of heat needed to VAPORIZE(boil) 1.0g of a substance *q=mHv is used to calculate how much energy absorbed when a substance BOILS or how much energy is released when a substance CONDENSES **(NO CHANGE IN TEMPERATURE)** |
Created by:
ZoeCards