Answer:
It is endothermic and entropy increases.
Explanation:
The answer is 1.6 atm. Let's first calculate the mole fraction of gas Y.
The mole fraction (x) is: x = n1/n, where n1 is a number of moles of an
individual gas in a mixture and n is total moles of the gas mixture. We
know that n1 of gas Y is 6.0 mol (n1 = 6.0 mol) and that there are in
total 8. mol of the gas mixture (n = 2.0 + 6.0 = 8.0 mol). Now calculate
the mole fraction of gas Y. x = 6.0/8.0 = 0.75. Now, let's use the mole
fraction of gas Y (x) and the total pressure (P) to calculate the
partial pressure of gas Y (P1): x = P1/P. P1 = x * P. If x = 0.75 and P =
2.1 atm, then the partial pressure of gas Y is: P1 = 0.75 * 2.1 atm =
1.6 atm.
Answer: There are several ways. The first that comes to mind is a pH meter. A pH electrode Is lowered into the solution, and (Assuming) the pH Meter has been properly calibrated, and the temperature of the solution is set to the calibration of the Meter, the pH can be read directly from an analogue scale or digital readout. Below 7 is acidic, 7 is Neutral, (like Pure Water), and over 7 is Alkaline, or Basic.
A useful, but less accurate method is the use of any number of “pH Indicator Solutions”, which are essentially a type of various colored dyes that change color within differing pH ranges. Usually, if the pH is unknown, a small amount of solution is removed from the container and tested separately - in a “well plate”, or similar method.
These types of dyes, or Indicator Solutions, can be dried upon strips of “pH indicator Paper”, which, depending upon the type can be very useful when carrying out more precisely arrived at pH tests like Titration.
Just to see if a solution is “Acid” or “Base”, Litmus paper is used; “a Red color shows Acidity, and a Blue color, a Base”; ergo, “An Acid Solution will turn Litmus Paper, Red”.
Answer:
6 moles of oxygen are needed to make 12 moles of magnesium oxide.
Explanation:
First of all you should know that the balanced chemical equation is:
2 Mg + O₂ → 2 MgO
The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three. Remember that proportionality is a constant relationship or ratio between different magnitudes.
If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:
a ⇒ b
c ⇒ x
So:

In this case the rule of three applies as follows: if 2 moles of magnesium oxide are produced from 1 mole of oxygen, 12 moles of magnesium oxide from how many moles of oxygen is produced?

moles of oxygen= 6
<u><em>6 moles of oxygen are needed to make 12 moles of magnesium oxide.</em></u>