As you said, the answer is 150.
But in all the numbers, there's a comma with two zeros, and so you have to put them in your answer : 150,00
They are the significative numbers.
Hope it helps
A cation is a positive charged ion and a anion is a negatively charged ion. An electron will make a cation if it is lost and a anion if it is gained.
The etymology of the prefix cat- means the way down: so think of the sun setting down and losing light. Cat = losing electrons (Such as in a CAThode ray).
The etymology of the prefix -an means upwards. So think of the sun rising up and becoming brighter. An = gaining electrons and becoming overall more negative as electrons are negatively charged.
Moles of O₂ = 3.92
<h3>Further explanation</h3>
Given
V=1 L
T=-118 °C + 273 = 155 K
P = 49.77 atm
Required
moles of O₂
Solution
the gas equation can be written
where
P = pressure, atm
V = volume, liter
n = number of moles
R = gas constant = 0.08206 L.atm / mol K
T = temperature, Kelvin
Input the value :
n= PV/RT
Answer: The mass in 
atoms of zinc is 0.405 g.
Explanation:
Given: Atoms of zinc =
It is known that 1 mole of every substance contains 
atoms. So, the number of moles in given number of atoms is as follows.
As moles is the mass of a substance divided by its molar mass. So, mass of zinc (molar mass = 65.39 g/mol) is calculated as follows.
Thus, we can conclude that the mass in atoms of zinc is 0.405 g.
You are looking for an element in the fourth period and a transition metal. As most have about 3 valence electrons. Gallium and Scandium work perfectly.
