Answer:
E = 19.89×10⁻¹⁶ J
λ = 1×10⁻¹ nm
Explanation:
Given data:
Frequency of xray = 3×10¹⁸ Hz
Wavelength of xray = ?
Energy of xray = ?
Solution:
speed of wave = wavelength × frequency
speed = 3×10⁸ m/s
3×10⁸ m/s = λ ×3×10¹⁸ s⁻¹
λ = 3×10⁸ m/s / 3×10¹⁸ s⁻¹
λ = 1×10⁻¹⁰m
m to nm:
λ = 1×10⁻¹⁰m×10⁹
λ = 1×10⁻¹ nm
Energy of x-ray:
E = h.f
h = plancks constant = 6.63×10⁻³⁴ Js
by putting values,
E = 6.63×10⁻³⁴ Js ×3×10¹⁸ s⁻
¹
E = 19.89×10⁻¹⁶ J
Answer:
2.53×10²³ atoms
Explanation:
To solve this, convert grams to moles and moles to atoms.
To convert grams to moles, use the molar mass of C₁₂H₂₂O₁₁ (342.296 g/mol). Divide the mass by the molar mass to get moles. Moles = 0.4207
To convert moles to atoms, use Avogadro's number (6.022×10²³ atoms/mol). Multiply moles by Avogadro's number to get atoms. Atoms = 2.53×10²³
The standard enthalpy of reaction should be negative.
<h3>What is enthalpy?</h3>
A thermodynamic quantity equivalent to the total heat content of a system. It is equal to the internal energy of the system plus the product of pressure and volume.
Inside the heat pack are two chemicals that get mixed when you smush them together. As they mix, some weak bonds are broken, which takes a little bit of energy. But new, stronger bonds form which release energy. Releasing that energy causes the surroundings to heat up.
Hence, option B is correct.
Learn more about enthalpy here:
brainly.com/question/13775366
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So it's good to map out what you know you have and work from there:
We have two liter measurements and one mole measurement, and we need to find the moles.
For this problem, think of it this way: 46 liters of gas = 1.4 moles.
If one side changes, the other has to as well (if the liters decrease, the moles decrease. if the liters increase, so do the moles.) What you can do is put this into a fraction:
<span><u>1.4 moles</u></span>
46 L <span> </span>
if we know that each liter of gas is equal to x amount of moles, we know that 11.5 liters equals some amount of moles. You can put this into a fraction too, and make it equal to the other fraction:
<span><u>1.4 moles</u></span> = <u>x moles</u>
46 L 11.5 L
Then get your calculator out and do some algebra.
11.5 * (1.4/46) = x
The answer should come out to be: 0.35 moles
