Heat, q=mCD, & calorimeter
Ex. 1 How many Calories should a label read if a piece of candy gives off 3.78 x 103 Kilojoules of heat?
Ex 2 A breakfast of cereal, orange juice, and milk might contain 230 nutritional Calories. Express this energy in joules.
Ex. 3 A copper pot with a temperature of 25C and a mass of 1350 g ( 3 lbs) was put on a warm stove coil, the temperature of the pot then increased to 48C. Copper has a specific heat of 0.385 J/gC, what was the amount of heat supplied to the pot to cause the temperature change?
Ex. 4 When 435 J of heat is added to 3.4g of olive oil at 21C, the temperature increases to 85C. What is the specific heat of olive oil?
Ex 5 A small pebble is heated and placed in a foam cup calorimeter continuing 25.0 mL of water at 25.0°C. The water reaches a maximum temperature of 26.4 °C. How many joules of heat were released by the pebble?
Homework Problem A: A fruit-and oatmeal bar contains 142 nutritional Calories. Convert this energy to joules.
Homework Problem B: A 155g sample of an unknown substance was heated from 25.0°C to 40.0°C. In the process, the substance absorbed 5694J of energy. What is the specific heat of the substance? Identify the substance. ( look at table 1)
Phy D
Ex.6 How much heat is absorbed when 24.8 g water is evaporated?
Ex 7 How much heat is transferred when 400 grams of mercury (Hg) is vaporized?
Ex 8 If 300 kJ of heat is available, how much copper can be melted?
Ex 9 How much heat is transferred when 100 grams of ethyl alcohol condenses?
Ex 10 If 700 calories are available, how much sulfur can be solidified?
Homework Problem C: Water is sprayed on oranges during a frosty night. If an average of 11.8g of water freezes on each orange, how much heat is released?
Heat, q=mCD, & calorimeter
Ex. 1 How many Calories should a label read if a piece of candy gives off 3.78 x 103 Kilojoules of heat?
Ex 2 A breakfast of cereal, orange juice, and milk might contain 230 nutritional Calories. Express this energy in joules.
Ex. 3 A copper pot with a temperature of 25C and a mass of 1350 g ( 3 lbs) was put on a warm stove coil, the temperature of the pot then increased to 48C. Copper has a specific heat of 0.385 J/gC, what was the amount of heat supplied to the pot to cause the temperature change?
Ex. 4 When 435 J of heat is added to 3.4g of olive oil at 21C, the temperature increases to 85C. What is the specific heat of olive oil?
Ex 5 A small pebble is heated and placed in a foam cup calorimeter continuing 25.0 mL of water at 25.0°C. The water reaches a maximum temperature of 26.4 °C. How many joules of heat were released by the pebble?
Homework Problem A: A fruit-and oatmeal bar contains 142 nutritional Calories. Convert this energy to joules.
Homework Problem B: A 155g sample of an unknown substance was heated from 25.0°C to 40.0°C. In the process, the substance absorbed 5694J of energy. What is the specific heat of the substance? Identify the substance. ( look at table 1)
Phy D
Ex.6 How much heat is absorbed when 24.8 g water is evaporated?
Ex 7 How much heat is transferred when 400 grams of mercury (Hg) is vaporized?
Ex 8 If 300 kJ of heat is available, how much copper can be melted?
Ex 9 How much heat is transferred when 100 grams of ethyl alcohol condenses?
Ex 10 If 700 calories are available, how much sulfur can be solidified?
Homework Problem C: Water is sprayed on oranges during a frosty night. If an average of 11.8g of water freezes on each orange, how much heat is released?
Chem D
Ex. 11: Calculate the kilojoules of heat required to decompose 2.24 mol NaHCO3 (s). 2NaHCO3 (s) è Na2CO3 (s) + H2O (g) + CO2 (g) rH = 129 kJ
Ex 12. How much heat is released when 8.0 g of oxygen react in: C2H4 (g) + 3O2 (g) è 2CO2 (g) + 2 H2O (l) + 1411kJ.
Ex 13. Given the equation Si (s) + 2Cl2 (g) è SiCl2 (l) + 687 kJ , how much heat is produced when 106 grams of chlorine reacts?
Ex. 14. Calculate the amount of heat produced when 52.4 g of methane, CH4, burns:
CH4 (g) + 2O2 (g) èCO2 (g) + 2H2O (l) DH = - 890.2 kJ
Homewok Problem D: Glycine is important for biological energy. The combustion of glycine is given by the following equation: 4C2H5O2N (s) + 9O2 (g) è 8CO2 (g) + 10 H2O (l) + 2N2 (g) + 3857 kJ .Is this reaction endothermic or exothermic? If there is 5 grams of glycine, how much energy will be given off/absorbed?

Chem D

Ex. 11: Calculate the kilojoules of heat required to decompose 2.24 mol NaHCO3 (s). 2NaHCO3 (s) è Na2CO3 (s) + H2O (g) + CO2 (g) rH = 129 kJ

Ex 12. How much heat is released when 8.0 g of oxygen react in: C2H4 (g) + 3O2 (g) è 2CO2 (g) + 2 H2O (l) + 1411kJ.

Ex 13. Given the equation Si (s) + 2Cl2 (g) è SiCl2 (l) + 687 kJ , how much heat is produced when 106 grams of chlorine reacts?

Ex. 14. Calculate the amount of heat produced when 52.4 g of methane, CH4, burns:

CH4 (g) + 2O2 (g) èCO2 (g) + 2H2O (l) DH = - 890.2 kJ

Homewok Problem D: Glycine is important for biological energy. The combustion of glycine is given by the following equation: 4C2H5O2N (s) + 9O2 (g) è 8CO2 (g) + 10 H2O (l) + 2N2 (g) + 3857 kJ .Is this reaction endothermic or exothermic? If there is 5 grams of glycine, how much energy will be given off/absorbed?