Vocabulary
What does the first law of thermodynamics state?
Energy can not be created nor destroyed just transferred.
Two formulas for finding work?
w=(f)(d) and w=(-P^V)
Gases A(g) and B(g) are confined in a cylinder-and-piston arrangement like that in Figure 5.4 and react to form a solid product C(s): A1g2 + B1g2 ¡ C1s2. As the reaction occurs, the system loses 1150 J of heat to the surroundings. The piston moves downward as the gases react to form a solid. As the volume of the gas decreases under the constant pressure of the atmosphere, the surroundings do 480 J of work on the system. What is the change in the internal energy of the system?
∆E = q + w = 1-1150J2 + 1480J2 = -670J
(a) Large beds of rocks are used in some solar-heated homes to store heat. Assume that the specific heat of
the rocks is 0.82 J/g-K. Calculate the quantity of heat absorbed by 50.0 kg of rocks if their temperature increases by 12.0 °C. (b) What temperature change would these rocks undergo if they emitted 450 kJ of heat?
a) 4.9*10^5J
b)11K/C
Calculate ∆H for the reaction
NO(g) + O(g) --> NO21(g)
given this following information
NOg + O3g -->NO2(g) + O2(g) ∆H = -198.9kJ
O3g --> 3/2O2(g) ∆H=-142.3kJ
O2(g) --> 2Og ∆H = 495.0kJ
-304.1kj
Define potential and kinetic energy.
Potential Energy= Energy possessed due to position or chemical composition
Kinetic Energy: Energy possessed due to position
What is the formula for finding internal energy and how do you know if energy was gained or lost?
E=q+w or E=Final energy - Initial Energy
A fuel is burned in a cylinder equipped with a piston. The initial volume of the cylinder is 0.250 L, and the final volume is 0.980 L. If the piston expands against a constant pressure of 136.8 kPa, how much work (in J) is done?
w = -P∆V = -1136.8 kPa210.730 L2 = 99.8 L@kPa
When 50.0 mL of 0.100 M AgNO3 and 50.0 mL of 0.100 M HCl are mixed in a constant-pressure calorimeter, the temperature of the mixture increases from 22.30 to 23.11 °C. The temperature increase is caused by the following reaction:
AgNO3(aq) + HCl(aq) --> AgCl(s) + HNO3(aq)
Calculate ∆H for this reaction in kJ/mol AgNO , assuming that the combined solution has a mass of 100.0g and a specific heat of 4.18 J/g-°C.
-68.kj/mol or -68,000J/mol
During a deep breath, our lungs expand about 2.0L against an external pressure of 101.3 kPa. How much work is in- volved in this process (in J)?
w=203 j
Meaning of exothermic and endothermic.
Exothermic: Energy is being released
Endothermic: Energy is being absorbed
This formula is used to find what?
Eel=k(Q1Q2)/d
Electrostatic Potential Energy which shows the interaction between two charged particles.
How much heat is released when 4.50 g of methane gas is burned in a constant-pressure system?
When a student mixes 50 mL of 1.0M HCl and 50mL of 1.0M NaOH in a coffee cup calorimeter, the temperature of the resultant solution increases from 21.0 to 27.5 °C. Calculate the enthalpy change for the reaction in kJ/mol HCl, assuming that the calorimeter loses only a negligible quantity of heat, that the total volume of the solution is 100 mL, that its density is 1.0 g/mL, and that its specific heat is 4.18 J/g-K.
∆H = -2.7 kJ/0.050 mol = -54 kJ/mol
(a)What amount of heat(injoules)is required to raise the temperature of 1 g of water by 1 kelvin? (b) What amount of heat (in joules) is required to raise the temperature of 1 mole of water by 1 kelvin? (c) What is the heat capacity of 370 g of liquid water? (d) How many kJ of heat are needed to raise the temperature of 5.00 kg of liquid water from 24.6 to 46.2 °C?
a) 4.184J
b)75.4 J
c)1548 J/k
d) 452 kj
Difference between internal energy and enthalpy?
Formula for enthalpy and change in enthalpy?
H=E+PV or change in ^H=Hproducts-Hreactants
Hydrogen peroxide can decompose to water and oxygen by the reaction
2H2O2(l)+ 2H2O(l) + O2(g) ∆H = -196kJ
Calculate the quantity of heat released when 5.00g of H2O2(l) decomposes at constant pressure.
question is on pg:222
-14.4kj
The combustion of methylhydrazine CH6N2, a liquid rocket fuel, produces N2(g) + CO2(g), and H2O(l)
2CH6N2(l)+5O2(g) --> 2N2(g)+2CO2(g)+6H2O(l)
When 4.00 g of methylhydrazine is combusted in a bomb calorimeter, the temperature of the calorimeter increases from 25.00 to 39.50 °C. In a separate experiment the heat capacity of the calorimeter is measured to be 7.794 kJ/°C. Calculate the heat of reaction for the combustion of a mole of CH6N2.
-1.30 * 10^3kJ/mol CH6N2
What is the relationship between the repulsion and attraction in relation to electro potential energy and charges of atoms (ie; like charges/opp. charges).
Like Charges: As the particles get closer, repulsion increases, Eel increases. As the particles move farther away, repulsion decreases, Eel decreases.
Opposite Charges: As the particles get closer, attraction increases, Eel decreases. As the particles move farther apart, attraction decreases, Eel increases.
What is this formula used to find?
Cs=J/(g)(^T)
Specific Heat
a) How much heat is needed to warm 250 g of water (about 1 cup) from 22 °C (about room temperature) to 98 °C (near its boiling point)? (b) What is the molar heat capacity of water?
a) 7.9 * 10^4 J
b)75.2J/mol-K
Carbon occurs in two forms, graphite and diamond. The enthalpy of the combustion of graphite is -393.5 kJ/mol, and that of diamond is -395.4 kJ/mol:
C1graphite + O2g --> CO2(g) ∆H = -393.5kJ C1diamond + O2g -->CO2(g) ∆H = -395.4kJ
Calculate ∆H for the conversion of graphite to diamond:
C1graphite2 --> C1diamond2 ∆H = ?
+1.9kJ