Answer:
In order to answer the question, we convert the measurements given to a common base unit. For this case, we use seconds.
A) 0.02 seconds
B) 0.02 teraseconds x (10^12 s / 1 terasecond) = 2x10^10 seconds
C) 2,500 milliseconds x (1 s / 1000 ms) = 2.5 seconds
D) 25,000 nanoseconds x (1 x 10^-9 s / 1 nanosecond) = 2.5 x 10^-5 seconds
So ,The correct answer is option " D "
i) Las bacterias son organismos microscópicos unicelulares que prosperan en diversos entornos. Estos organismos pueden vivir en el suelo, el océano y dentro del intestino humano.
ii) Un virus es un agente infeccioso submicroscópico que se replica solo dentro de las células vivas de un organismo. Los virus infectan todas las formas de vida, desde animales y plantas hasta microorganismos, incluidas bacterias y arqueas.
Explanation:
According to law of conservation of mass, mass of the reactants is equal to the mass of products in a chemical equation. As mass can neither be created nor it can be destroyed but it can be transformed from one form to another.
As it is given that hydrogen and in excess oxygen is reacting that leads to the formation of water. Hence, the chemical reaction equation will be as follows.

Since, it is given that 4 mol of hydrogen is reacting with excess of oxygen and gives 2 moles of water.
Hence, number of moles of water produced is calculated as follows.
4 mol of 
= 4 moles of 
Thus, we can conclude that 4 moles of water you can produce from 4.0 mol of hydrogen and excess oxygen.
Answer:
P=atm

Explanation:
The problem give you the Van Der Waals equation:

First we are going to solve for P:


Then you should know all the units of each term of the equation, that is:







where atm=atmosphere, L=litters, K=kelvin
Now, you should replace the units in the equation for each value:

Then you should multiply and eliminate the same units which they are dividing each other (Please see the photo below), so you have:

Then operate the fraction subtraction:
P=

And finally you can find the answer:
P=atm
Now solving for b:




Replacing units:

Multiplying and dividing units,(please see the second photo below), we have:


