What is meant by the specific heat capacity of a substance?
It is the amount of energy required to increase the temperature of one gram of a body by one Kelvin unit, expressed as J/K/g. The specific heat capacity also can be measured in J/K/Kg and J/K/mol.
Substance Specific heat Capacity (J/K/g)
Water 4.18 acetone 2.17 hexane 2.26
Compare the specific heat capacity of water with a range of other solvents.
The table compares the heat capacities of water and two other solvents.
Compare the specific heat capacity of water to other substances (e.g ethanol) providing an example of why water is used in industry based on this property.
Results & calculations 힓H = mC힓T
Methanol CH3OH Propenol C3H8O Ethanol C2H5OH m = 3.6g m= 3.4g m=8.3g C = 4.18 (Specific heat capacity of water) C = 4.18 (Specific heat capacity of water) C = 4.18 (Specific heat capacity of water) ∆T=30C degrees ∆T=24C degrees ∆T=44C degrees N.M of methanol = 0.1125 mol. N.M of propenol = 0.0566 mol. N.M of ethanol= 0.1804 mol. ∆H=(3.6*4.18*30)/(0.1125) = 111466.6667 KJ/Mol ∆H=(3.4*4.18*24)/(0.056) =6090.857 JK/Mol ∆H=(8.3*4.18*44)/(0.1804) =8461.951JK/Mol The specific heat capacity of water is used in industry. For example, power plants and factories use water as steam to turn turbines in power generators and as a coolant to condense the steam. The water is then returned to the water body warmer than it was when it was drawn. Nevertheless, if we compared the specific heat capacity of water to the ethanol heat capacity, the ethanol cannot be used for the same industry as the water. The reason is because the ethanol has less capacity 2.44 while the water capacity is 4.18. Higher heat capacity store more energy, thus water stores more energy per degree raised than ethanol. Explain how water’s ability to absorb heat is used to measure energy changes in chemical reactions. The water is the medium that absorbs the heat from something else, allowing for the determination if the reaction was endothermic or exothermic. Since the water increases in temperature, heat is being absorbed. When the temperature change is known, this can be converted into a change in heat; that is energy by using the formula: 힓H = -mC힓T. This formula tells us how much energy we would need to raise 1 kg of the substance by 1 K. The negative sign is included if the reaction was exothermic. State a reason why water is used to measure energy changes in chemical reactions. The reasons are that water has a high specific heat because of the hydrogen bonding. This increases intermolecular forces between molecules. As a result of being the hydrogen bonding is the strongest type of non-covalent bond, a lot of energy is required to break these strong hydrogen bonds. Thus, more energy is needed and thus the specific heat capacity is high for water. Moreover, water is a universal solvent and is found everywhere. Describe a method to measure the change in temperature when substances dissolve in water. To measure the change in temperature when substances dissolve in water we used the calorimetry experiment. Procedure: 1.Measure a beaker’s weight 2.Pour the 100mL of water into a beaker 3.Measure 100mL of water 4.Record the beaker’s weight 5. Put …show more content…
Repeat steps 4-7 using ethanol and propane.
14. Calculate the molar heat to measure the change in temperature when substances dissolve in water using the formula ∆H=mC∆T.
Calorimetry experiment or method is the process of measuring the amount of heat released or absorbed throughout a chemical reaction. By knowing the change in heat, it can be determined if a reaction is exothermic or endothermic. Some substances dissolve in some solutions and produce energy in the form of heat. These dissolution reactions are known as exothermic reactions. Example on the exothermic reactions is the reaction between sulphuric acid and water. When we put the sulphuric acid into water amount of heat is being produced. Exothermic reactions are characterised by negative heat flow (-ΔH). H2O + H2SO4 ---------> (HSO4) - + (H3O) +
Another example on endothermic reactions is Photosynthesis. In this process, plants use the energy from the sun to convert carbon dioxide and water into glucose and oxygen. This reaction needs 15MJ of energy from sunlight for every kilogram of glucose that is produced Sunlight + 6CO2 (g) + H2O (l) ---------> C6H12O6 (aq) + 6O2
It is the amount of energy required to increase the temperature of one gram of a body by one Kelvin unit, expressed as J/K/g. The specific heat capacity also can be measured in J/K/Kg and J/K/mol.
Substance Specific heat Capacity (J/K/g)
Water 4.18 acetone 2.17 hexane 2.26
Compare the specific heat capacity of water with a range of other solvents.
The table compares the heat capacities of water and two other solvents.
Compare the specific heat capacity of water to other substances (e.g ethanol) providing an example of why water is used in industry based on this property.
Results & calculations 힓H = mC힓T
Methanol CH3OH Propenol C3H8O Ethanol C2H5OH m = 3.6g m= 3.4g m=8.3g C = 4.18 (Specific heat capacity of water) C = 4.18 (Specific heat capacity of water) C = 4.18 (Specific heat capacity of water) ∆T=30C degrees ∆T=24C degrees ∆T=44C degrees N.M of methanol = 0.1125 mol. N.M of propenol = 0.0566 mol. N.M of ethanol= 0.1804 mol. ∆H=(3.6*4.18*30)/(0.1125) = 111466.6667 KJ/Mol ∆H=(3.4*4.18*24)/(0.056) =6090.857 JK/Mol ∆H=(8.3*4.18*44)/(0.1804) =8461.951JK/Mol The specific heat capacity of water is used in industry. For example, power plants and factories use water as steam to turn turbines in power generators and as a coolant to condense the steam. The water is then returned to the water body warmer than it was when it was drawn. Nevertheless, if we compared the specific heat capacity of water to the ethanol heat capacity, the ethanol cannot be used for the same industry as the water. The reason is because the ethanol has less capacity 2.44 while the water capacity is 4.18. Higher heat capacity store more energy, thus water stores more energy per degree raised than ethanol. Explain how water’s ability to absorb heat is used to measure energy changes in chemical reactions. The water is the medium that absorbs the heat from something else, allowing for the determination if the reaction was endothermic or exothermic. Since the water increases in temperature, heat is being absorbed. When the temperature change is known, this can be converted into a change in heat; that is energy by using the formula: 힓H = -mC힓T. This formula tells us how much energy we would need to raise 1 kg of the substance by 1 K. The negative sign is included if the reaction was exothermic. State a reason why water is used to measure energy changes in chemical reactions. The reasons are that water has a high specific heat because of the hydrogen bonding. This increases intermolecular forces between molecules. As a result of being the hydrogen bonding is the strongest type of non-covalent bond, a lot of energy is required to break these strong hydrogen bonds. Thus, more energy is needed and thus the specific heat capacity is high for water. Moreover, water is a universal solvent and is found everywhere. Describe a method to measure the change in temperature when substances dissolve in water. To measure the change in temperature when substances dissolve in water we used the calorimetry experiment. Procedure: 1.Measure a beaker’s weight 2.Pour the 100mL of water into a beaker 3.Measure 100mL of water 4.Record the beaker’s weight 5. Put …show more content…
Repeat steps 4-7 using ethanol and propane.
14. Calculate the molar heat to measure the change in temperature when substances dissolve in water using the formula ∆H=mC∆T.
Calorimetry experiment or method is the process of measuring the amount of heat released or absorbed throughout a chemical reaction. By knowing the change in heat, it can be determined if a reaction is exothermic or endothermic. Some substances dissolve in some solutions and produce energy in the form of heat. These dissolution reactions are known as exothermic reactions. Example on the exothermic reactions is the reaction between sulphuric acid and water. When we put the sulphuric acid into water amount of heat is being produced. Exothermic reactions are characterised by negative heat flow (-ΔH). H2O + H2SO4 ---------> (HSO4) - + (H3O) +
Another example on endothermic reactions is Photosynthesis. In this process, plants use the energy from the sun to convert carbon dioxide and water into glucose and oxygen. This reaction needs 15MJ of energy from sunlight for every kilogram of glucose that is produced Sunlight + 6CO2 (g) + H2O (l) ---------> C6H12O6 (aq) + 6O2