Answer:
B. The student should model a convex lens because it directs light toward the center of the lens.
Explanation:
Lenses are optical devices that work on the principle of refraction.
Refraction is a phenomenon of wave (such as light waves) that occurs when a ray of light crosses the interface between two mediums with different optical density: when this occurs, the ray of light bends and change speed.
In particular, there are two types of lenses:
- Convex lenses: these lenses are curved outward at their center, therefore the rays of light coming from infinite distance (parallel to the axis) are all focused into a point of the lens, called principal focus. Therefore, a convex lens directs lights towards this point.
- Concave lenses: these lenses are curved inward at their center, therefore the rays of light coming from infinite distance are bent away from the principal focus. Therefore, this is a diverging lens, as the rays of light do not converge.
So, the correct answer is
B. The student should model a convex lens because it directs light toward the center of the lens.
Apples are rich in fiber and antioxidants. Eating them is linked to a lower risk of many chronic conditions, including diabetes, heart disease, and cancer. Apples may also promote weight loss and improve gut and brain health.
Answer:
Living organisms/chemical processes that support life
Answer:
After three hours, concentration of C₂F₄ is 0.00208M
Explanation:
The rate constant of the reaction:
2 C2F4 → C4F8 is 0.0410M⁻¹s⁻¹
As the units are M⁻¹s⁻¹, this reaction is of second order. The integrated law of a second-order reaction is:
![\frac{1}{[A]} =\frac{1}{[A]_0} +Kt](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B%5BA%5D%7D%20%3D%5Cfrac%7B1%7D%7B%5BA%5D_0%7D%20%2BKt)
<em>Where [A] and [A]₀ represents initial and final concentrations of the reactant (C₂F₄), K is rate constant (0.0410M⁻¹s⁻¹) and t is time of the reaction (In seconds).
</em>
3.00 hours are in seconds:
3 hours ₓ (3600 seconds / 1 hour) = 10800 seconds
Initial concentration of C2F4 is:
0.105mol / 4.00L = 0.02625M
Replacing in the integrated law:
![\frac{1}{[A]_0}= \frac{1}{0.02625} +0.0410M^{-1}s^{-1}*10800s\\\frac{1}{[A]_0}=480.9M^{-1}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B%5BA%5D_0%7D%3D%20%5Cfrac%7B1%7D%7B0.02625%7D%20%20%2B0.0410M%5E%7B-1%7Ds%5E%7B-1%7D%2A10800s%5C%5C%5Cfrac%7B1%7D%7B%5BA%5D_0%7D%3D480.9M%5E%7B-1%7D)
[A] = 0.00208M
<h3>After three hours, concentration of C₂F₄ is 0.00208M</h3>