Answer:
<span>The mole concept is important in chemistry because, "</span>Atoms and molecules are very small and the mole concept allows us to count atoms and molecules by weighing macroscopic amounts of material".
Explanation:
To understand this question lets take an example of Hydrogen atom. Let suppose you need to react Hydrogen with Oxygen. You need exactly Two Hydrogen atoms and one Oxygen atom to form one water molecule.
The mass of 1 hydrogen atom is 1.76 × 10⁻²⁴ grams. How will you count the Hydrogen atoms??? How can you measure exactly for 1 Million Hydrogen Atoms???
Answer to these questions and Calculations lies in Mole. It is found that 1 Mole of Hydrogen weights exactly 1.008 gram and contains 6.022 × 10²³ atoms. Now, having this reference in hand you can calculate for any number of Hydrogen atoms.
Result:
So the Mole helps us to zoom a microscopic level to a macroscopic level. :)
Answer:
Isotopes are atoms of the same element with the same number of protons but different number of neutrons.
Hope this helps.
Answer: The molecular formula will be 
Explanation:
Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.
Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.
The empirical formula is 
The empirical weight of = 1(12)+3(1)= 15g.
The molecular weight = 45.0 g/mole
Now we have to calculate the molecular formula:
The molecular formula will be=
Thus molecular formula will be
Answer:
H2 + I2 --> 2HI
Explanation:
The two reactants are diatomic molecules because they contain two atoms of the same element. Therefore, they would need to have a subscript of "2" next to their symbols.
When balancing an equation, you want the same amount and type of atoms on both sides. By adding a coefficient of "2" in front of the product, two H's and two I's are now on both sides.
Answer:
A. The lens spreads light.
Explanation:
The convex lens will converge the light that passes through it. The direction of light will be bend to be closer to the middle point. This is the lens used for the eyeglass that treat people with hypermetropia. That is why the convex lens also called a converging lens or a plus lens. The strength of the convex lens depends on its focal length, index of the material used, and the radius of curvature.
