Answer:
ΔH° = -1815 kJ
Explanation:
The balanced chemical equation
C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l)
tells us that 2220 kJ joules are released in the combustion of one mol propane,C3H8 . So what we need to solve this problem is to find how many moles of propane 20.0 L represent and do the calculation.
To do that, we will be using the Ideal Gas Law since we are told the volume, temperature, and pressure.
PV = nRT ∴ n = PV/RT
P: 1 atm
V: 20.0 L
R= 0.08206 Latm/kmol ( R constant for ideal gases)
T= 25 ºC + 273 = 298 k (Need to convert T to degree Kelvin)
Plugging the values
n = 1 atm x 20.0 L/ (0.08206 Latm/ k mol)
n = 0.82 mol
ΔH° =(-2220 kJ / 1 mol C3H8 ) 0.82 mol C3H8 = -1815 kJ
Compound X is an isomer of butane with different chain types. It is either straight chain or bend chain.
Iodine react with nitric acid to produce iodic acid, nitrogen dioxide and water.
Answer:
option b is correct option = (6.76×10¹⁴ Hz)
Explanation:
Given data:
Wavelength of photon = 4.42×10⁻⁷ m
Speed of light = 2.99×10⁸ m/s
Frequency of radiation = ?
Solution:
Formula:
Speed of wave = frequency × wavelength
Now we will rearrange this formula.
frequency = Speed of wave / wavelength
f = c/ λ
f = 2.99×10⁸ m/s / 4.42×10⁻⁷ m
f = 0.676×10¹⁵ Hz (s⁻¹ = Hz)
f = 6.76×10¹⁴ Hz
Thus option b is correct option.
Carbon is the reference taken to assign the atomic mass unit
- One twelfth of the mass of unbound carbon-12 is taken as 1amu
- The unit for the atomic mass constant is Dalton (Da)
- This unit is standard when doing calculations in chemistry and physics
- 1amu = 1.6605x10⁻¹⁹g
- This was also derived from the law of definite proportions
- This standard has been set by the International Union of Pure and Applied Chemistry (IUPAC)
- The IUPAC is responsible for assigning various standards such as the nomenclature of various compounds, and updating the periodic table of elements.
- According to the IUPAC carbon is the reference taken to assign the atomic mass unit
Learn more about atomic mass units here:
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