2H2 + O2 ---->2H2O
number of moles in reaction 2 mol 1 mol 2 mol
number of liters in the reaction 2*22.4 L 1*22.4 L 2*22.4L
We can see that volumes of the gases are proportional to coefficients in the reaction ( if gases are under the same conditions), so we can write
2H2 + O2 ---->2H2O
2 L 1 L 2 L
given 40 L ( 25 L) 40 L
We can see that we have excess of O2,
because if 2 L H2 are needed 1 L O2, then 40 L of H2 are needed 20 L O2.
So, limiting reactant is H2, and we will need to calculate Volume of H2O using H2.
2L H2 give 2L H2O(gas), so 40 L H2 give 40 L H2O.
Pressure is inversely related to temperature
Answer:

Explanation:
Hello,
In this case, since the Lewis theory is based on the bonds formation between atoms via the valence electrons, we can verify the chemical formula of the compound formed by strontium and nitrogen by noticing that strontium has two valence electrons as it is in group IIA, for that reason, two nitrogens should be available for bonding. Therefore, since nitrogen is in group VA, it is said that three electrons are required to attain the octet (maximum amount bonded electrons), for that reason, three strontiums are should be available for bonding. In such a way, the formula should be:

Regards.
One mole of any element is Avogadro's number, which is 6.02 * 10^23 atoms.
One mole of Calcium is equal to its atomic weight in grams, 1 mole Ca = 40.08 x 1000 mg = 6.02 * 10^23 atoms.
We have 8.6mg of Ca which means 8.6mg / 40,080mg = .00021457 of a mole of calcium.
Now multiply that by Avogadro's number which gives number of atoms = 0.00021457 * 6.02 * 10^23 atoms. So the answer is 1.292 * 10^20 atoms of Ca.
I’m not sure what you’re asking but- halogens are among the most active nonmetals due to their electron configuration and number of valence electrons.