calculate the frequency in hertz of electromagnetic radiation that has a wavelength of 720.0 nm. (c= 3.00 X 10^8 m/s)
1 answer:
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Answer:
Explanation:
This is a problem in calorimetry — the measurement of the quantities of heat that flow from one object to another.
It is based on the Law of Conservation of Energy — Energy can be transformed from one type to another, but it cannot be destroyed or created.
If heat flows out of the reactor (negative), the same amount of heat must flow into the water (positive).
Since there is no change in total energy,
heat₁ + heat₂ = 0
The symbol for the quantity of heat transferred is q, so we can rewrite the word equation as
q₁ + q₂ = 0
The formula for the heat absorbed or released by an object is
q = mCΔT, where
m = the mass of the sample
C = the specific heat capacity of the sample, and
ΔT = T_f - T_i = the change in temperature
1. Equation
There are two heat flows in this problem,
heat released by reactor + heat absorbed by water = 0
q₁ + q₂ = 0
q₁ + m₂C₂ΔT₂ = 0
2. Data:
q₁ = -23 746 kJ
m₂ = ?; C₂ = 4.184 J°C⁻¹g⁻¹; T_f = 95 °C; T_i = 10 °C
3. Calculations
(a) Convert kilojoules to joules
(b) ΔT
ΔT₂ = T_f - T_i = 95 °C - 10 °C = 85 °C
(c) m₂
Answer:
Similarities: both state the mass of chemical species and they have the same numerical value
Differences: molecular mass refers to one single molecule and molar mass refers to one mole of a molecule
Explanation:
The molecular mass is the value of the mass of each molecule and it is measured in mass units (u). It is calculated adding the mass of each atom of the molecule.
The molar mass is the value of the mass of one mole of molecules, which means the mass of 6.022140857 × 10²³ molecules. The unit is g/mol.
For example, we can consider the methane molecule, which has the chemical formula of CH₄:
Molecular mass CH₄ = C mass + 4 x (H mass)
Molecular mass CH₄ = 12.01 + 4 x (1.01)
Molecular mass CH₄ = 16.05 u
Now to calculate the molar mass we multiply the value of the molecular mass by the Avogadro number and convert the units to g/mol:
Molar mass CH₄: 16.05 x x 6.022140857 × 10²³ mol⁻¹
Molecular mass CH₄ = 16.05 g / mol