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In what direction does heat flow between two objects?
Heat always flows from a warmer object to a cooler object.
How do endothermic processes differ from exothermicprocesses?
In an endothermic process, the system gains heat as the surroundings cool down. In an exothermic process, the system loses heat as the surroundings heat up.
What units areused to measure heat flow?
Heat flow is measured in two common units, the calorie and the joule.
On what factors does the heat capacity of an object depend?
The heat capacity of anobject depends on both its mass and its chemical composition
Using calories, calculate how much heat 32.0 g of water absorbs when it is heated from 25.0°C to 80.0°C. How many joules is this?6. A chunk of silver has a heat capacity of 42.8 J/°C and a mass of 181 g. Calculate the specific heat of silver.
7. How many kilojoules of heat are absorbed when 1.00 L of water isheated from 18°C to 85°C?
Using calories, calculate how much heat 32.0 g of water absorbs when it is heated from 25.0°C to 80.0°C. How many joules is this?
q = m c ΔT
q= (32 g)(1.00cal/g-°C )(80°C – 25°C)
q = 1760 cal
q= (32 g)( 4.18 J/g -°C)(80°C – 25°C)
q = 7356.8 Joules
A chunk of silver has a heat capacity of 42.8 J/°C and a mass of 181 g. Calculate thespecific heat of silver.
42.8J/°C = 0.236J/g/°C.
181g
How many kilojoules of heat are absorbed when 1.00 L of water is heated from 18°C to 85°C?
1kg x 4.18kJ/kg/°C x 67°C(85 - 18) = 280.06kJ
Writing Activity
Explanatory Paragraph
Use the concept of heat capacity to explain why on a sunny day the concrete deck around an outdoor swimming pool becomeshot, while the water stays cool.
Heat capacity depends on both mass and chemical compositions. The greater the mass of an object, the greater the heat capacity. Concrete has a lower heat
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