Answer:
The bond energy of F–F = 429 kJ/mol
Explanation:
Given:
The bond energy of H–H = 432 kJ/mol
The bond energy of H–F = 565 kJ/mol
The bond energy of F–F = ?
Given that the standard enthalpy of the reaction:
<u>H₂ (g) + F₂ (g) ⇒ 2HF (g)</u>
ΔH = –269 kJ/mol
So,
<u>ΔH = Bond energy of reactants - Bond energy of products.</u>
<u>–269 kJ/mol = [1. (H–H) + 1. (F–F)] - [2. (H–F)]</u>
Applying the values as:
–269 kJ/mol = [1. (432 kJ/mol) + 1. (F–F)] - [2. (565 kJ/mol)]
Solving for , The bond energy of F–F , we get:
<u>The bond energy of F–F = 429 kJ/mol</u>
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Answer:
470 N.
Explanation:
Using equations of motion:
S = vi*t + 1/2*(a*(t^2))
Given:
S = 0.65 m
t = 1.5 s
vi = 0 m/s
0.65 = 1/2 * (a * (1.5)^2)
a = 1.3/2.25
= 0.578 m/s^2
Force = mass * acceleration due to gravity
= 92 * 0.578
= 53.16 N
Total force = 420 + 53.16
= 473.16 N
= 470 N.
Answer:
Option C, acting as waves and particles
Explanation:
Light has dual nature because it acts both as a wave and particle. It has high energy particle i.e photons and it also behave as an electromagnetic wave. This property of light is studied under the quantum mechanics. Einstein also proved that light is a stream of photons possessing both electrical and magnetic properties.
Hence, option C is correct
A prism is a piece of glass or plastic in the shape of a triangle. A prism works because the different colors of light travel at different speeds inside the glass. Because the colors of light travel at different speeds, they get bent by different amounts and come out all spread out instead of mixed up.
Refraction is the bending of a wave when it enters a medium where its speed is different. The refraction of light when it passes from a fast medium to a slow medium bends the light ray toward the normal to the boundary between the two media. Refraction is responsible for image formation by lenses and the eye.