<span>The right answer is D. In a situation where the sound wave reaches the ear and the reflected wave reaches the ear less than 0.1 seconds later, the individual would not be able to hear an echo. There needs to a far more significant delay between the sound and the reflection of said sound reaching the listener's ear for the echo effect to become apparent.</span>
Answer:
PBr3 - Molecule , Polar
N2H2 - Molecule , (Polar in E- form and Non- polar in Z form)
C2H2 - Molecule , Non- Polar
N2 - Molecule , Polar
NCl3 - Molecule , Polar
SiF4 - Molecule , Non- Polar
NH3 - Molecule , Polar
F - Not- Molecule (atom)
H2 - Molecule and Non- Polar
Explanation:
Molecule : these are group of two or more atoms joined by strong force of attraction.
H2 is non- polar because it is homoatomic molecule.(made up of same element)
N2 is non- polar because it is homoatomic molecule.
Its A. because it measures the rate of the decay of the isotope
We know that to relate solutions of with the factors of molarity and volume, we can use the equation:

**
NOTE: The volume as indicated in this question is defined in L, not mL, so that conversion must be made. However it is 1000 mL = 1 L.
So now we can assign values to these variables. Let us say that the 18 M

is the left side of the equation. Then we have:

We can then solve for

:

and

or

We now know that the total amount of volume of the 4.35 M solution will be
210 mL. This is assuming that the entirety of the 50 mL of 18 M is used and the rest (160 mL) of water is then added.
The mesosphere is the coldest of the atmospheric layers. In fact it is colder than the Polar regions of the Earth cold enough to freeze water vapor into ice clouds. As you increase in altitude, temperature decreases The thermosphere is the layer to which this pattern does not apply.