I'm guessing D or C, remember that the noble gases cannot combine
It’s one... electron affinity
We will assume helium to behave as an ideal gas and apply the ideal gas law:
PV = nRT
For pressure measured in atmospheres and volume measured in liters, the value of the molar gas constant is 0.082. Therefore:
T = PV / nR
T = (2.57 x 15.5) / (1.2 x 0.082)
T = 404.8 Kelvin
Answer:

Explanation:
Hello,
In this case, the molecular chemical reaction is:

Thus, by considering the ionic species we have:

Wherein the ammonium and bromide ions are spectator ions since nickel (II) phosphate is largely insoluble in water, therefore, the net ionic equation is:

Best regards.
Half-life can be given as the time required by the substance to reduce to half of its original concentration. The original mass of Uranium was 11.2 grams.
<h3>What is the expression of half-life?</h3>
The half-life for the reaction can be expressed as;

Where the final mass of the product is, 
The time for the reduction is given as, 
The half-life of the compound is given as, 
The original concentration (
) of the Uranium is given as,

The original mass of uranium-232 has been 11.2 grams.
Learn more about half-life, here:
brainly.com/question/24710827