If the element has a charge of +2 it has lost two electrons giving it an overall positive charge making it a cation. In order to find the number of electrons, take the elements atomic number and subtract two since it lost two electrons
Answer:
E. None of these
Explanation:
We know, By GAS laws,
PV = NRT, where p- pressure, v- volume, n- number of moles, R- gas constant ,and T- temperature
Now, In the question, the number of moles remains the same as the gas is the same. so n is constant so we can compare n before and after a temperature change.
= 
where P1= 1 atm, P2 = 10 atm, V1= 20 mL, T1= 10°C and T2= 100°C
We don't have to worry about the standard units as they are present equally on both the sides and get cut, same goes for R( gas constant)
So putting values, we get

Cutting, R on both sides and moving contents to the right so that only V2 is left on the left.

∴ V2 = 
∴ V2 = 20mL
Answer:
balanced equation mole ratio 5 2 mol NO/1 mol O2
10.00 g O2 3 1 mol O2/32.00 g O2 5 0.3125 mol O2
20.00 g NO 3 1 mol NO/30.01 g NO 5 0.6664 mol NO
actual mole ratio 5 0.6664 mol NO/0.3125 mol O2 5 2.132 mol NO/1.000 mol O2
Because the actual mole ratio of NO:O2 is larger than the balanced equation mole
ratio of NO:O2, there is an excess of NO; O2 is the limiting reactant.
Mass of NO used 5 0.3125 mol O2 3 2 mol NO/1 mol O2 5 0.6250 mol NO
0.6250 mol NO 3 30.01 g NO/1 mol NO 5 18.76 g NO
Mass of NO2 produced 5 0.6250 mol NO2 3 46.01 g NO2/1 mol NO2 5 28.76 g NO2
Excess NO 5 20.00 g NO 2 18.76 g NO 5 1.24 g N
Explanation:
Networks of feeding relationships is correct