Read 10.1 to 10.3 After reading each section write one sentence summarizing the section. This will be turned in!
Energy and Specific Heat Date:
What is the symbol for heat? q
Heat flows from a _____ object to a _____ object. Warmer; cooler
Heat is a form of… ENERGY
What is energy? The ability to do work.
Can energy be destroyed? NO! It is transferred! From high to low.
How do we calculate energy? Energy = mass * specific heat * temperature change q = m*s* T T = T f – T i
Chemical Potential Energy Energy stored in chemical bonds.
Specific Heat The amount of heat necessary to raise the temperature of one gram of a substance one degree Celsius. (Water’s specific heat is one cal). J/g o C cal/g o C Constants to know –Specific heat of water is 1 cal/g o C or 4.184J/g o C –1000 cal = 1 Cal (box top calorie)
Low specific heats will heat up and cool down FAST. High specific heats will take longer to heat up and longer to cool down.
Beach set up
How much work do you have to do to work off a can of pop?? First figure Joules in can of pop. Then relate to Nm Calories in = calories.| J= | 1 calorie
Finding work 1 Joule = 1 Newton*meter Newton = mass * acceleration Acceleration due to gravity 9.8 m/s 2 1 Newton = X kg * 9.8 m/s 2 X = kg Lift 102 g 1 meter to expend 1 Joule of energy.
Since J of heat were used to raise the temperature of 160 g of wood to 150 o C, what was the original temperature of the wood? Specific heat of wood 1.8 J/g o C.
If -180 J of heat were released when the temperature of grain alcohol was lowered by 5 o C, how many grams of grain alcohol were present? (2 SF) Specific heat of grain alcohol 2.4 J/g o C.
How much heat in calories is necessary to raise the temperature of 163 g of silver 106 o C? Specific heat of silver 0.24 J/g o C (3 SF)
If 960 J of heat are added to 10 g of chloroform, what is the temperature change that will result? Specific heat of chloroform 0.96 J/g o C
If 1920 J of heat are used to heat 200g of silver to a temperature of 75 o C, what was the initial temperature of the silver? Specific heat of silver 0.24 J/g o C
If 4232 J of heat is used to heat 230 g of iron originally at 13 o C, what is the final temperature of the iron? Specific heat of iron 0.46 J/g o C
Beach check
Homework Solve equations using specific heat formula.