<h2>Answer:</h2>
The mass of the system will remain the same if there is no conversion of mass to energy in the reaction.
<h3>Explanation:</h3>
- If the system is closed, then according to the law of mass conservation the mass of the reaction system will remain the same.
- <u><em>Law of conservation of the mass: In simple words, it is described as the mass of a closed system can never be changed, it may transfer from one form to another or change into energy.</em></u>
- But if the reaction involves energy transfer like heat or light production, in this case, the mass can be changed.
<h3>
Answer:</h3>
250.756 moles He
<h3>
Explanation:</h3>
From the question we are given;
Volume, L = 685 L
Temperature, T = 621 K
Pressure, P = 189 × 10 kPa
We are required to calculate the number of moles of the gas,
Using the Ideal gas equation,
PV = nRT, where P is the pressure, V is the volume, T is the temperature, n is the number of moles, and R is the ideal gas constant.
We can replace the known variables and constant in the equation to get the unknown variable, n.
Using ideal gas constant as 8.3145 L.kPa/K/mol
n = 250.756 moles
The moles of helium contained in the sphere is 250.756 moles
The answer is (D) microscopic. You can remember this, because the name is very close to "microscope," an instrument used to greatly magnify and observe tiny organisms and objects.
Answer:
CU
Explanation:
Cu is the correct answer if I'm correct
Answer: option <span>A) increases from bottom to top within the group.
Explanation:
</span>It is a known trend that the metallic character of the elements increase from let to right and from top to bottom.
The greater the metallic character the greater the reactivity of the metal.
So, the elements of the columns 1 and 2 are the most reactive metals and among them the elements at the bottom are yet more reactive.
<span>The higher reactivity of the metals that are lower in the periodic table is attributed to the greater total number of electrons.
The greater the total number of electrons the more reactive the metals
as their outermost electrons (the valence electrons which are those that react) are located further from the nucleus and therefore they are held less
strongly, which makes them react more easily.</span>