CH6:Work & Heat/Specific Heat
A chemical reaction where heat is transferred to the surroundings is a(n) ________ reaction.
exothermic reaction
How much energy is required to heat 80 grams of water from 26oC to 48oC?
7.3x103 J
If 3.47mol of an ideal gas has a pressure of 2.85atm and a volume of 65.73L, what is the temperature of the sample? Give answer in Kelvin
658 K
What is the frequency of electromagnetic radiation having a wavelength of 2.1x10-7 m?
1.428x1015 s-1
What happens to an electron when it goes from a higher energy level to a lower energy level?
It releases energy as light
Which is true if H = -95 J?
A) Both the system and the surroundings are gaining 95 J.
B) Both the system and the surroundings are losing 95 J.
C) The system is gaining 95 J while the surrounding is losing 95 J
D) The surroundings is gaining 95 J while the system is losing 95 J
D
In a coffee-cup calorimeter, 100.0 g of H2O and 100.0 mL of HCl are mixed. The HCl had an initial temperature of 44.6oC and the water was originally at 24.6oC. After the reaction, the temperature of both substances is 31.3oC. Was the reaction exothermic or endothermic? Explain.
Exothermic, the temperature decreased from 44.6oC to 31.3oC indicating energy was released by the HCl.
An unknown gas with a mass of 205 g occupies a volume of 20.0 L at standard temperature and pressure. What is the molar mass of the gas?
230. g/mol
How much faster does hydrogen escape through a porous container than sulfur dioxide?
5.64
If ℓ = 1, what type of orbital is this?
p oribtal
How many grams of water can be heated from 20.0oC to 75.0oC using 12500.0 J?
54.3 grams
In a coffee-cup calorimeter, 100.0 g of H2O and 100.0 mL of HCl are mixed. The HCl had an initial temperature of 44.6oC and the water was originally at 24.6oC. After the reaction, the temperature of both substances is 31.3oC. Calculate how much heat the water lost or gained in Joules.
2.80 x 103 J
What volume of O2 gas at 25oC and 1.04 atm is needed for the complete combustion of 5.53 grams of propane (C3H8)?
C3H8 + O2 → CO2 + H2O
14.7 L
If a gas effuses 4.25 times faster than iodine gas (I2), what is its molar mass?
14.1 g/mol
A d subshell contains 5 orbitals. If all orbitals are fully filled, how many electrons are in one orbital?
2
5.0 g of copper was heated from 20°C to 80°C. How much energy (in J) was used to heat Cu? (Specific heat of Cu is 0.092 cal/g°C)
115 J
Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values:
2CO2(g) + H2O(g) → C2H2(g) + 5/2O2(g)
C2H2(g) + 2H2(g) → C2H6(g) ΔH=-94.5 kJ
H2O(g) → H2(g) + 1/2O2 (g) ΔH=71.2 kJ
C2H6(g) + 7/2O2(g) → 2CO2(g) + 3H2O(g) ΔH=-283 kJ
ΔH=235.1 kJ
Of the following gases, which one has density of 0.906 g/L at 315 K and 1.16 atm?
(a) Ne
(b) Ar
(c) Kr
(d) Xe
(e) He
A) Neon
A photon of light has an energy of 3.98×10-19J. Calculate the frequency of the photon.
6.01×1014Hz
If n = 3, what are the possible values of ℓ?
0,1,2
50.0 g of iron that has an initial temperature of 225 oC and 50.0 g of gold that has an initial temperature of 25.0 oC are brought into contact with one another. Assuming no heat is lost to the surroundings, what will be the temperature when the two metals reach thermal equilibrium? The specific heat capacity of iron=0.449 J/goC and gold=0.128 J/goC.
181 oC
When 1.00 g of fructose, C6H12O6(s), is burned in oxygen in a bomb calorimeter, the temperature of the calorimeter increases by 1.58 °C. If the heat capacity of the calorimeter and its contents is 9.90 kJ/°C, what is qrxn (in kJ/mol) for this combustion?
-2.82x103 kJ/mol
Calculate the density (in g/L) of C4H10 at 25°C and a pressure of 750 mmHg
2.3 g/L
A compound composed of carbon, hydrogen, and chlorine diffuses through a pinhole 0.411 times as fast as neon. Select the correct molecular formula for the compound:
(a) CH2Cl2
(b) CHCl3
(c) C2H2Cl2
(d) C2H3Cl
B
Determine if the following set of quantum numbers is valid or invalid:
n = 3, ℓ = 3, mℓ = 0, ms = +½
Invalid (ℓ must be less than n)