Specific Heat Pre Lab Specific Heat Different substances

Specific Heat Pre – Lab

Specific Heat • Different substances require different amounts of heat to change their temperature. • In general the specific heat of a substance indicates how hard something is to heat up or cool down. • Scientifically speaking the specific heat is the amount of heat required to change the temperature of 1 gram of a substance by 1ºC.

• Which substance is the hardest to heat up or cool down?

Sample Problem 1 • A 70. 00 g sample of metal is heated to 80. 0 C and placed in 100. 00 g of water at 22. 0 C in a styrofoam cup. The temperature of the water in the cup rises to 26. 4 C as the metal cools. Determine the specific heat of the metal.

Sample Problem 1 • A 70. 00 g sample of metal is heated to 80. 0 C and placed in 100. 00 g of water at 22. 0 C in a styrofoam cup. The temperature of the water in the cup rises to 26. 4 C as the metal cools. Determine the specific heat of the metal. What three things must we determine to find the specific heat? Look at the units for specific heat

Sample Problem 1 • A 70. 00 g sample of metal is heated to 80. 0 C and placed in 100. 00 g of water at 22. 0 C in a styrofoam cup. The temperature of the water in the cup rises to 26. 4 C as the metal cools. Determine the specific heat of the metal. What three things must we determine to find the specific heat? Look at the units for specific heat J/g °C Joules (Energy) Grams (mass) °C (temperature change)

Sample Problem 1 • A 70. 00 g sample of metal is heated to 80. 0 C and placed in 100. 00 g of water at 22. 0 C in a styrofoam cup. The temperature of the water in the cup rises to 26. 4 C as the metal cools. Determine the specific heat of the metal. • Mass of metal = 70. 00 g ∆T of metal = 53. 6°C • Heat gained by water = (mass of water)( T of water)(Cp of water) • Heat = (100. 00 g)(4. 4°C)(4. 184 J/g C) = 1840. 96 J = 1800 J • Heat gained by the water = Heat lost by the metal • To find specific heat remember the units: Cp = J/g ·°C

Sample Problem 2 • Calculate the percent error, of this measurement if the true value for the specific heat of the metal is 0. 50 J/g C.

Sample Problem 2 • Calculate the percent error, of this measurement if the true value for the specific heat of the metal is 0. 50 J/g C.

Sample Problem 2 • Calculate the percent error, of this measurement if the true value for the specific heat of the metal is 0. 50 J/g C.

Sample Problem 3 a • A 45. 00 g sample of metal is heated to 98. 0 C and placed in 100. 00 g of water at 21. 0 C in a styrofoam cup. The temperature of the water in the cup rises to 24. 0 C as the metal cools. (a) Determine the specific heat of the metal.

Sample Problem 3 a • A 45. 00 g sample of metal is heated to 98. 0 C and placed in 100. 00 g of water at 21. 0 C in a styrofoam cup. The temperature of the water in the cup rises to 24. 0 C as the metal cools. (a) Determine the specific heat of the metal. • Heat gained by water = (mass of water)( T of water)(Cp of water) • Heat gained by the water = Heat lost by the metal • Heat = (100. 00 g)(3. 0°C)(4. 184 J/g C) = 1255. 2 J = 1300 J H 1300 J J = Cpof metal = = 0. 39039 0. 39 o m x T (45. 00 g)(74. 0 C) go C g o. C

Sample Problem 3 b • Calculate the percent error, of this measurement if the true value for the specific heat of the metal is 0. 34 J/g C.

Homework • Lab Summary for Specific Heat of a Metal