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“The E n e r g y Associated with Phase Change” PROJECT. Ex: BORON. Properties of Elements. Melting Pt: 2079 o C (Chart) Heat of Fusion: 22.2 kJ/mol Change 2018 J/g Boiling Pt: 3675 o C ( Chart) Heat of Vaporization: 314 kJ/mol Change 28,545 J/g
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Ex: BORON Properties of Elements Melting Pt: 2079 oC(Chart) Heat of Fusion: 22.2 kJ/mol Change 2018 J/g Boiling Pt: 3675 oC (Chart) Heat of Vaporization: 314 kJ/mol Change 28,545 J/g Molar Mass: 11 g/mole (Per. Table) Specific Heat (Cp):1.03 J/g.C(Chart)
Change Heat of Fusion and Heat of Vaporization to J/g Heat of fusion: 22.2 kJ/mol Change 2018 J/g Hfus Heat of vaporization : 314 kJ/mol Change 28545 J/g Hvap
Purpose:Determine the energy (Q), in Joules, necessary to raise the temperature of 10.0 grams of the element from 10.0° C below the melting point to 10.0° C above the boiling point. Draw the phase change stair-step diagram. ·Label both axes with units and measurable quantity; ·Label the temperature axis with numbers. ·Also, label the melting point and boiling point. Write "A" at the initial temperature and a "B" at the final temperature on your plotted line.
temperature added energy Heating curves and DH
liquid solid gas Heating curves and DH temperature added energy
liquid solid gas Heating curves and DH melting/ freezing pt temperature added energy
liquid solid gas Heating curves and DH boiling/ cond. pt melting/ freezing pt temperature added energy
liquid solid gas Heating curves and DH boiling/condensing occurring here melting/freezing occurring here boiling/ cond. pt melting/ freezing pt temperature added energy
How is the total enthalpy change (DH) calculated for a substance whose temperature change includes a change in state?
temperature Dt of solid absorbing energy added energy
temperature Q = m x CsolidxDt added energy
the energy absorbed as a solid melts becomes potential energy, so no Dt temperature Q= m x CsolidxDt added energy
Q = mass x Hfus temperature Q= m x CsolidxDt added energy
Dt of liquid absorbing energy Q = mass x DHfus temperature Q = m x CsolidxDt added energy
Q = mass x DHfus Q = m x CliquidxDt temperature Q = m x CsolidxDt added energy
the energy absorbed as a liquid boils becomes potential energy, so no Dt Q = mass X DHfus Q = m x CliquidxDt temperature Q = m x CsolidxDt added energy
Q = mass X DHfus Q = m x CliquidxDt temperature Q = m x CsolidxDt added energy
Dt of gas absorbing energy Q = mass X DHvap Q = mass X DHfus Q = m x CliquidxDt temperature Q = m x CsolidxDt added energy
Q = m x CgasxDt Q = mass X DHvap Q = mass X DHfus Q = m x CliquidxDt temperature Q = m x CsolidxDt added energy
Q = m x CgasxDt Q = mass X DHvap Q = mass X DHfus Q = m x CliquidxDt temperature Q = m x CsolidxDt added energy
How many calculations for Q are required to determine the energy of this element according to the specifications listed in the Purpose? _______ Boron (J/g)
How many calculations for Q are required to determine the energy of this elementaccording to the specifications listed in the Purpose?
The DH of any substance being heated will be the sum of the DH of any Dt occurring plus DH of any phase change occurring Q = m x CgasxDt Q = mass X DHvap Q = mass X DHfus Q = m x CliquidxDt temperature Q = m x CsolidxDt added energy
The DH of any substance being heated will be the sum of the DH of any Dt occurring plus DH of any phase change occurring Q = m x CgasxDt Q = mass x Hvap Q = mass x Hfus Q = m x CliquidxDt temperature Q = m x CsolidxDt added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? Q = m x CgasxDt Q = mass X DHvap Q = mass X DHfus Q = m x CliquidxDt temperature Q = m x CsolidxDt added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? 50 oC temperature 0 oC -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? use the following values: Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = 4.186 J/goC 50 oC temperature 0 oC -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? use the following values: Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = 4.186 J/goC 50 oC Q = m x CliquidxDt Q = mass X DHfus temperature 0 oC Q = m x CsolidxDt -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? use the following values: Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = 4.186 J/goC 50 oC Q3 = m x CliquidxDt Q = mass X DHfus temperature 0 oC Q1 = 10g x 2.1 J/goC x20oC -20 oC added energy
DH2=10 g x 1mol/18g x 6.01kJ/mol EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? use the following values: Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = 4.186 J/goC 50 oC Q3 = m x CliquidxDt Q2=10 g x 1mol/18g x 6.01 kJ/mol temperature 0 oC Q1 = 10g x 2.1 J/goC x 20oC -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? use the following values: Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = 4.186 J/goC Q3 = 10g x 4.186 J/goC x 50 oC 50 oC Q2=10 g x1mol/18g x 6.01 kJ/mol temperature 0 oC Q1 = 10g x 2.1 J/goC x 20oC -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? use the following values: Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = 4.186 J/goC total DH = DH1 + DH2 + DH3 Q3 = 10g x 4.186 J/goC x 50 oC 50 oC Q2=10 g x1mol/18g x 6.01 kJ/mol temperature 0 oC Q1 = 10g x 2.1 J/goC x 20oC -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? use the following values: Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = 4.186 J/goC total DH = DH1 + DH2 + DH3 = 420 J + 3340 J + 2093 J Q3 = 10g x 4.186 J/goC x 50 oC 50 oC Q2=10 g x1mol/18g x 6.01 kJ/mol temperature 0 oC Q1 = 10g x 2.1 J/goC x 20oC -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? use the following values: Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = 4.186 J/goC total DH = DH1 + DH2 + DH3 5853 J = 420 J + 3340 J + 2093 J Q3 = 10g x 4.186 J/goC x 50 oC 50 oC Q2=10 g x1mol/18g x 6.01 kJ/mol temperature 0 oC Q1 = 10g x 2.1 J/goC x 20oC -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? It takes 5853 joules to heat up 10 grams of water from -20 oC to +50 oC. Q3 = 10g x 4.186 J/goC x 50 oC 50 oC Q2=10 g x1mol/18g x 6.01 kJ/mol temperature 0 oC Q1 = 10g x 2.1 J/goC x 20 oC -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? It takes 5853 joules to heat up 10 grams of water from -20 oC to +50 oC. Q3 = 10g x 4.186 J/goC x 50 oC 50 oC Q2=10 g x1mol/18g x 6.01 kJ/mol temperature 0 oC Q1 = 10g x 2.1 J/goC x 20 oC -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC? It takes 5853 joules to heat up 10 grams of water from -20 oC to +50 oC. 50 oC temperature 0 oC -20 oC 5853 J added energy