Answer:
Copy and paste "Electromagnetic waves are categorized according to their frequency f or, equivalently, according to their wavelength λ = c/f. Visible light has a wavelength range from ~400 nm to ~700 nm. Violet light has a wavelength of ~400 nm, and a frequency of ~7.5*1014 Hz. Red light has a wavelength of ~700 nm, and a frequency of ~4.3*1014 Hz." into google, and the correct website pops up as the first result.
Explanation:
I tried to link the website that I use to convert wavelengths and frequencies into types of light, but it deleted my answer, so I guess we're doing it this way. As for converting the wavelength to energy, the same principles apply as before:
Frequency: ν Wavelength: λ Energy: E Speed of light: C (3.00e8) Planck's Constant: h (6.626e-34)
ν -> λ λ = C/ν
λ -> ν ν = C/λ
For either of these equations, wavelength must be converted to meters or nanometers, depending on the equation.
For ν -> λ, after doing the equation, convert the wavelength into nanometers by dividing by 1e-9.
For converting λ -> ν, convert the wavelength into meters by multiplying by 1e-9.
For energy: E = hν = hc/λ
Molality is defined as the number of moles of solute in 1 kg of solvent.
molality of solution to be prepared is 0.50 molal
this means that in 1000 g of water there should be 0.50 mol of NaCl
if 1000 g of water should contain - 0.50 mol
then 750.0 g of water requires - 0.50 mol/kg x 0.750 kg = 0.375 mol
mass of NaCl in 0.375 mol - 58.5 g/mol x 0.375 mol = 21.9 g
therefore a mass of 21.9 g of NaCl is required
Answer:
The pH of the buffer is 7.0 and this pH is not useful to pH 7.0
Explanation:
The pH of a buffer is obtained by using H-H equation:
pH = pKa + log [A⁻] / [HA]
<em>Where pH is the pH of the buffer</em>
<em>The pKa of acetic acid is 4.74.</em>
<em>[A⁻] could be taken as moles of sodium acetate (14.59g * (1mol / 82g) = 0.1779 moles</em>
<em>[HA] are the moles of acetic acid (0.060g * (1mol / 60g) = 0.001moles</em>
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Replacing:
pH = 4.74 + log [0.1779mol] / [0.001mol]
<em>pH = 6.99 ≈ 7.0</em>
<em />
The pH of the buffer is 7.0
But the buffer is not useful to pH = 7.0 because a buffer works between pKa±1 (For acetic acid: 3.74 - 5.74). As pH 7.0 is out of this interval,
this pH is not useful to pH 7.0
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Answer:
The tension in the string is 78.73 N.
Explanation:
The tension in the string can be determined from the expression;
v = 
where: v is the speed of the wave in the sting, T is the tension in the string and m is the mass per unit length of the sting.
Given that: v = 16.2 m/s, and m = 0.3 kg/m.
Then;
16.2 = 
Square both sides to have,
= 
T = x 0.3
= 252.44 x 0.3
= 78.732
T = 78.732 N
The tension in the string is 78.73 N.
