Answer:
It's the first option. A distance between two similar points on a wave of light.
Explanation:
On a wavelength chart, where you measure the rate at which the light travels at its distance from the source. You have two points to compare to.
Answer:
See explanation
Explanation:
If we look at the structure of X, we will discover that X is an organic compound. The compound will certainly have a much lower melting point than sand.
This is because, sand is composed of high melting point inorganic materials.
Hence, even though the researcher accidentally spilled some sand into the the beaker containing the crystalline substance X, he does not need to be perturbed since the melting point of X is much lower than that of sand
Explanation:
A change that does not cause any change in chemical composition of a substance is known as a physical change.
For example, mass, density, volume etc are all physical changes.
On the other hand, a change that brings change in chemical composition of a substance is known as chemical change.
For example, combustion, toxicity, reactivity etc are all chemical changes.
Hence, following statements are identified as chemical or physical changes as follows.
(a) Oxygen gas supports combustion : Chemical change
(b) Fertilizers help to increase agricultural production : Chemical change
(c) Water boils below 
on top of a mountain : Physical change
(d) Lead is denser than aluminum : Physical change
(e) Uranium is a radioactive element : Chemical change
<span>A theory that has been proven true repeatedly over time and never disproven is called a law</span>
The molarity of the solution is 0.260 M
<u><em>calculation</em></u>
step 1: calculate the moles of NaOH
moles = mass÷ molar mas
= 5.20 g÷ 40.00 g/mol= 0.13 moles
Step 2: find the molarity of solution
molarity = moles÷volume in liters
=0.13 moles÷ 0.500 L = 0.260 M
