9.01 × 10⁻²⁶ J
<h3>Explanation</h3>
ΔE = h · f
Where
- ΔE the change in energy,
- h the planck's constant, and
- f frequency of the emission.
However, only λ is given.
f = c / λ
Where
- f frequency of the emission,
- λ wavelength of the emission, and
- c the speed of light.
For this emission:
f = 2.998 × 10⁸ / 2.21 = 1.36 × 10⁸ s⁻¹.
ΔE = h · f = 6.626 × 10⁻³⁴ × 1.36 × 10⁸ = 9.01 × 10⁻²⁶ J
Answer:
You need to heat the mixture to 78.37°C
Explanation:
In distillation, you can separate 2 or more compounds based on their difference in boiling points.
In a mixture of ethanol and water, in theory, you need to heat the mixture to 78.37°C. In this temperature, the ethanol must be evaporated and then condensed in the receiving flask.
Answer:
D) atomic radii increase from top to bottom of a group
Explanation:
Atomic radii trend along group:
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
As the size of atom increases the ionization energy from top to bottom also decreases because it becomes easier to remove the electron because of less nuclear attraction and as more electrons are added the outer electrons becomes more shielded and away from nucleus.
Other options are incorrect because,
A) atomic radii increase from left to right across the period
Correct = atomic radii decreases from left to right across the period
B) ionization energy increases from top to bottom within a family
Correct = ionization energy decreases from top to bottom within a family
C) electronegativity decreases from left to right across a period
Correct = electronegativity increases from left to right across a period
79470.2mL
Explanation:
Given:
Volume = 21gallons
problem, convert to milliliters;
gallons to milliliters
1 liter = 1.057 quarts
1 gallon = 4 quarts
we can simply solve this by establishing and using a conversion factor of 1 ;
1 gallon = 4 quarts
1.057 quarts = 1 liter
0.001L = 1mL
21gallons x 
= 79470.2mL
we say;
From;
1gallon = 3784.2mL
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conversion brainly.com/question/1548911
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