Answer is: molar mass of xylene 106,18 g/mol.
m(xylene) = 7,94 g.
m(cyclohexane) = 132,5 g.
T (solution) = - 4,9 °C.
Tf(cyclohexane) = 6,5 °C, frezing point.
Kf(cyclohexane) = 20,2 K·kg/mol; cryoscopic constant.
ΔT(solution) = 6,5°C - (-4,9°C) = 11,4°C = 11,4 K.
M(xylene) = Kf · m(xylene) ÷ m(cyclohexane) · ΔT(solution).
M(xylene) = 20,2 K·kg/mol · 7,94 g ÷ 0,1325 kg · 11,4 K.
M(xylene) = 106,18 g/mol.
Answer:- The wavelength is
and the right option is D.
Solution:- Wavelength is inversely proportional to the frequency and the equation is:

where,
is the wavelength, c is the speed of light and
is frequency.
Frequency is
and the speed of light is
.
Since, 
So, 
Let's plug in the values in the equation:


Hence, the right option is D)
.
When methane is burned out in the ocean
Answer:
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air.
Explanation:
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