The empirical formula is K₂O.
The empirical formula is the <em>simplest whole-number ratio</em> of atoms in a compound.
The <em>ratio of atom</em>s is the same as the <em>ratio of moles</em>.
So, our job is to calculate the <em>molar ratio</em> of K to O.
Step 1. Calculate the <em>moles of each element
</em>
Moles of K = 32.1 g K × (1 mol K/(39.10 g K =) = 0.8210 mol K
Moles of O = 6.57 g O × (1 mol O/16.00 g O) = 0.4106 mol 0
Step 2. Calculate the <em>molar ratio of each elemen</em>t
Divide each number by the smallest number of moles and round off to an integer
K:O = 0.8210:0.4106 = 1.999:1 ≈ 2:1
Step 3: Write the <em>empirical formula
</em>
EF = K₂O
It depends on the substance,but for most substance it is in the gaseous state.
I'm pretty sure its the weight of the book
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.
