Chap6.energy
Help!
|
|
||||
|---|---|---|---|---|---|
| energy | defined at the ability to do work
🗑
|
||||
| potential energy | stored energy; gasoline in a tank
🗑
|
||||
| kinetic energy | energy of motion - water going over a dam is kinetic energy
🗑
|
||||
| heat | Energy associated with the motion of particles in a substance
🗑
|
||||
| Joule (J) | Scientific unit of enery & work - kilojoule used more often (joule is very small) Ex. heating water for tea uses 75,000 J or 75kJ of heat
🗑
|
||||
| Calorie | Latin "caloric" meaning heat - originally defined as the amount of energy need to rasie the temp. of one gram of water by 1 degree Centigrade
🗑
|
||||
| 1 calorie equals _____ Joules | 1 cal =4.184 J
🗑
|
||||
| activation energy | the energy needed to break the bonds of reacting molecules
🗑
|
||||
| What is needed for chemical reaction to take place? | The molecules of the reactants must come in contact--collide, break bonds & make new bonds
🗑
|
||||
| Heat of reaction | Heat of reaction is amount of heat absorbed or release during a reaction that takes place at constant pressure
🗑
|
||||
| Heat of reaction (equation) | (temp sign - triangle) = Hproducts minus H reactants
🗑
|
||||
| Endothermic reaction | Ex. (lab) when table salt NaCL dissolves in water, energy to break the ionic bonds between the Na+ and the Cl- is needed; the energy comes from the water and can be measured by a drop in temperature
🗑
|
||||
| Endothermic reaction - another example | Rock salt is added to the water/ice used to make ice cream because the rock salt will rob the water of its heat as it break down into Na+ and Cl-
🗑
|
||||
| Exothermic | a reaction that gives off heat Ex. "heat packs" use the heat given off by rusting iron
🗑
|
||||
| endothermic reaction - is the energy greater with the reactants or the products? | Endothermic - Energy of the products is greater-the products have absorbed the energy - ex. Water plus heat equals gas
🗑
|
||||
| Endothermic - what does curve of reaction look like? | curve of reactants starts low, activation energy climbs, then curve is slightly down--but energy is absorbed by products, so curve is higher at end
🗑
|
||||
| Exothermic reaction | Curve of reaction starts high, activation energy is reached, then heat is released, so that energy curve is lower at the end
🗑
|
||||
| specific heat | A quantity of heat that changes the temperature of exactly 1 g of a substance by exactly 1 degree Centigrade
🗑
|
||||
| Specific heat | Refers to the fact that every substance has it own characteristic ability to absorb heat
🗑
|
||||
| Specific heat (equation) | Specific heat (SH) = heat/grams x delta Temperature = calories (or joules)/ 1 gram x 1 degree Centigrad
🗑
|
||||
| Rate these by Specific heat: water, aluminum, ammonia, copper | Aluminum (lowest), copper, ammonia, water
🗑
|
||||
| Water has a high specific heat, therefore | water requires MORE energy to bring it up by 1 degree C; therefore the body can use its water to absorb or release heat to maintain constant temperature
🗑
|
||||
| Heat equation | Use the value of the specific heat of a substance to calculate heat lost or gained during a reaction
🗑
|
||||
| Heat equation - Ex. | Heat = mass x temperature change x specific heat
🗑
|
||||
| 1 Calorie (with a capital C) equal | 1000 calories; 1 Calorie is actually a kilocalorie
🗑
|
||||
| Calorimeter | Device surrounded by water which burns food substances and records the heat released during the burn; this is calculated to determine the caloric content of the food
🗑
|
||||
| Caloric value: carbohydrates | 4 kcal per 1 gram of carbohydrate
🗑
|
||||
| Caloric value - fat (lipid) | 9 kcal per 1 gram of fat
🗑
|
||||
| Caloric value - protein | 4 kcal per 1 gram of fat
🗑
|
||||
| 4 - 9 - 4 | carbos - fats - protein "carbo 54 where are you?" (4 , the 4 &5 make 9, then 4 again)
🗑
|
||||
| How many kilocalories in cake w/35 g of carbohydrate, 10 g of fat & 5 g of protein? Equation | 35 g x 4kcal/1 g; then 10 g x 9 kcal/1 gram ; then 5 g x 4 kcal/1 g
🗑
|
||||
| Equation for caloric value | Multiply # of grams (fat, etc) by standard 4 kcal/1 g then add up values
🗑
|
||||
| Matter | Anything that occupies space and has mass
🗑
|
||||
| Solid (matter) 4 characteristics | a state of matter that has its own shape and volume - definite shape may be a crystal
🗑
|
||||
| Liquid | A state of matter that takes the shape of its container by has a definite volume
🗑
|
||||
| Gas | A state of matter characterized by no definite shape or volume. Particles in gas move rapidly
🗑
|
||||
| boiling | the formation of bubbles of gas throughout a liquid
🗑
|
||||
| Dipole-dipole attraction | attractive forces in molecules occur bewtween the positive end of one molecul and negative end of another
🗑
|
||||
| Hydrogen bond | Attractive force between partially positive hydorgen atom & the strongly enlectronegative atoms F, O or N - major factor in biological molecules, DNA
🗑
|
||||
| Dispersion forces | weak dipole bonding that still enables some substances to form temporary bonds
🗑
|
||||
| Ionic bond | Ex. NaCL - between atoms - a metal & nonmetal - very strong
🗑
|
||||
| Change of state - matter | matter is converted from one state to another
🗑
|
||||
| Melting point | the temperature at which a solid becomes a lliquid (melts) it is the same temperature as the freezing point
🗑
|
||||
| Freezing point is the ______ as the melting point | Freezing point is the same temperature as the freezing point
🗑
|
||||
| Heat of fusion | during melting energy called the heat of fusion is needed to separate the particles of a solid
🗑
|
||||
| Calculate heat of fusion (equation) | heat = mass x heat of fusion
🗑
|
||||
| sublimation | solid changes directly to gas
🗑
|
||||
| What is sbublimation useful? | Because freeze-dried foods do not need refrigeration because bacteria cannot grow without moisture
🗑
|
||||
| Deposition | Gas changes directly to solid
🗑
|
||||
| Evaporation | Water molecules escape from the liquid surface and enter the gas phase
🗑
|
||||
| Boiling point (bp) | All the molecules have the energy needed to change into gas
🗑
|
||||
| Boiling | Boiling of a liquid occurs as gas bubbles form throughout the liquid, then rise to surface and escape
🗑
|
||||
| Condensation - | Water changes from vapor (gas) back to liquid form
🗑
|
||||
| Heat of vaporization | Energy needed to vaporize 1 g of liquid to gas at its boiling point
🗑
|
||||
| Heating and Cooling Curves | Diagram used to illustrate changes of state
🗑
|
||||
| On a cooling curve, what does the plateau at 100 degrees centigrade represent? | (blank)
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
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
Created by:
walterina4327