First of all, as you seen the gases are noble which means that will not react with each other and in this case each gas create individual pressure.
P
= total pressure
P
= pressure of neon
P
= pressure of argon
P
= pressure of helium {which is required}
P
= P
+ P
+ P
1.25 = 0.68 + 0.35 + P
P
= 1.25 - [0.68 + 0.35] = 0.22 atm
Answer:
The heat of reaction when hydrogen and oxygen combine to form water is :
<u>C. 571.6 kJ</u>
Explanation:
Enthalpy Change = The enthalpy change for the formation of 1 mole of the substance from their standard state is called the enthalpy of formation.
This is intensive quantity as it is fixed for 1 mole .
Intensive properties = Those properties which are independent on the amount of the substance are intensive properties.
The value of these quantities does not get halve if you divide the substance into two equal parts. example , density, refractive index.
However , the enthalpy of reaction is extensive. Because on increasing the amount the value of the enthalpy also get doubles
Hence for this reaction :

Its value is -285.8 kJ for 1 mole
And here two moles are present . so the value of molar enthalpy is:
-285.8 x 2 = -571.6 kJ
Answer:
By balancing the chemical equation
Explanation:
The Law of Conservation of Matter states that matter cannot be destroyed nor created.
That is, you must have the same amount of matter before and after a reaction.
Atoms are made of matter, so you must have the same number of each type of atom in the reactants as in the products. You must balance the equation.
Consider the reaction
2H₂ + O₂ ⟶ 2H₂O
You must have 2s in front of H₂ and H₂O to balance the atoms.
They give you four atoms of H and two atoms of O on each side of the arrow.
The pressure of gas will increase because gaseous state is the final state and even if the heat added is evaporating some more gas is still added. It also depends on the temperature of heat added, if the temperature doesn't change the it's most likely for the pressure to be stable...
Hope it helps
Memorize that molarity = moles/liters and you can get these