Chemistry
The relationship between a gas's volume and pressure when its temperature is constant.
indirectly proportional
Water has a low vapor pressure because
it has strong hydrogen bonds acting between its molecules.
Water exists as a _____________ at 700 mmHg and 50 °C.
liquid
What change occurs from E to C?
melting
At 10 atm, dry ice is heated from -100 °C to 30 °C. What changes occur?
melting, then boiling
The SI units J/g°C J/Kg °C Cal/g°C measures
specific heat
Heat is a flow of energy caused by
temperature differences
What change occurs from C to D?
vaporization
What would happen to the liquid substance if the pressure were decreased until a phase change occurred? It would undergo...
vaporization
What is the normal melting point of this substance
-50 °C
What is the substance's melting point?
-60 C
What is the specific heat of an unknown substance if 100.0 g of it at 200.0 °C reaches an equilibrium temperature of 27.1 °C when placed in water. The mass of the water is 75. g and it has an initial temperature of 20.00 °C? (Specific heat of water is 4.18 J/g°C) (calorimeter problem)
0.127 J/g°C
What is the boiling point of water when the external pressure is 120 kPa?
105oC
What is the normal boiling point of ethanoic acid?
117oC
The specific heat(c) of copper is 0.39 J/g °C. What is the temperature change(∆t) when 100 Joules of heat(Q) is added to 20 grams? (q =mCΔT)
12.82 °C
At constant temperature, the pressure on 8 liters of a gas in increased from 1 atm to 4 atm. What will be the new volume of the gas?
2 L
A piece of metal with a mass of 32.8 g is heated to 100.5°C and dropped into 138.2 g of water at 20.0°C. The final temperature of the system is 30.2°C. What is the specific heat capacity of the metal? (calorimeter problem)
2.56 J/g°C
A sample of iron receives 50.J of heat energy that raises the temperature of the iron 25.0°C. If iron has a specific heat of 0.10 J/g°C, what is the mass of the iron sample? (q =mCΔT)
20 g
A 200 mL sample of a gas has a pressure of 1 atm. If the volume of the gas is decreased to 50 mL at constant temperature, the new pressure of the has will be
4 atm
The strongest intermolecular forces of attraction exist in a liquid whose heat of vaporization is
400 cal/g
A piece of metal, heated to 78oC is added to 130g of water at 21oC. The final temperature of the water is 23.2oC. Calculate the mass of the metal, if the specific heat capacity of the metal is .46 J/goC. (calorimeter problem)
47.4 g
What does "q" mean?
A change in heat energy
Which of the following would increase the pressure on a system?
All of the above: Increase the Temperature Pump in more gas Decrease the volume
Why does a gas with a lower vapor pressure have a higher boiling point?
All of the above: its molecules need more energy in order to break free from strong attraction there are strong forces of attraction between its particles it has a lower volatility
Copper, Stainless Steel, Carbon Steel, and Zinc were all heated using 10,000 JOULES of thermal energy. Based on the chart, which material would have the SMALLEST change in temperature?
Carbon Steel
A reaction is performed in a beaker with a temperature probe recording the temperature changes of the reaction. If the temperature began at 15.0 degrees Celsius and ended at 27.5 degrees Celsius. Is the reaction endothermic or exothermic?
Exothermic
A 1 gram sample of which substance, in a sealed 1 liter container, will occupy the container completely and uniformly
H2O (g), because one gram of H2O is equal to 1 liter
There are four cups of hot cocoa. The cup sizes are shown. The temperature of the cocoa in each cup is 25 degrees celsius. Which cup has the MOST thermal energy?
Large cup (Trenta)
For a skillet, used for cooking, do you want a high or low specific heat
Low, so that it will change temperature quickly
The molecules of which substance have the highest average kinetic energy?
N2 (g) @ 60 oC
In which region(s) of the graph would the substance be a liquid and a gas?
Region 4
Which is not true about the liquid state of matter?
The liquid state has a definite volume and a definite shape
As the temperature of H2O in a closed system decreases, what happens to its vapor pressure? Explain
The vapor pressure decreases, because at lower temperatures the intermolecular forces are stronger and there are fewer vapor particles.
For a particular substance, melting and freezing occur at the same temperature!
True
Water has a specific heat of 4184 J/KgºC. Wood has a specific heat of 1760 J/KgºC. What material needs more energy to raise the temperature 1ºC
Water
When the atmospheric pressure equals the equilibrium vapor pressure ___ occurs
boiling
At standard pressure, which element at 25oC could undergo a change of phase when the temperature is decreased?
chlorine, based off of chart