Hey there!
* Converts 1750 dm³ in liters :
1 dm³ = 1 L so 1750 dm³ = 1750 liters
* Convertes 125,000 Pa in atm : 
1 Pa = 9.86*10⁻⁶ atm so 9.86*10⁻⁶ / 125,000 => 1.233 atm
* Convertes 127ºC in K :
127 + 273.15 => 400.15 K
R = 0.082 atm.L/mol.K
Finally, it uses an equation of clapeyron :
p * V = n * R * T
1.233 * 1750 = n * 0.082 * 400.15
2157.75 = n * 32.8123
n = 2157.75 / 32.8123
n = 65.76 moles
hope this helps!
 
        
                    
             
        
        
        
It would be false sulfur has 6 
        
             
        
        
        
Answer:
m H2(g) = 2.241 g H2(g)
Explanation:
- 2Al(s) + 3H2SO4(aq) → Al2(SO4)3(aq) + 3 H2(g)
 
limit reagent:
∴ Mw Al = 26.982 g/mol
∴ Mw H2SO4 = 98.0785 g/mol
⇒ n Al = (20 g Al)×(mol/26.982 g) = 0.7412 mol Al
⇒ n H2SO4 = ( 115 g H2SO4 )×(mol/98.0785 g) = 1.173 mol H2SO4
⇒ n H2 = (0.7412 mol Al)×(3 mol H2/ 2 mol Al) = 1.112 mol H2
∴ Mw H2 = 2.016 g/mol
⇒ g H2 = (1.112 mol H2)×(2.016 g/mol) = 2.241 g H2
 
        
             
        
        
        
Electrons absorb energy, as they absorb energy they go from ground state to excited state and to return to ground state electrons release energy in the form of photons producing that color.
 
        
             
        
        
        
Alkaline Earth Metals are the elements located in the second period from the left of the periodic table. These elements lose two electrons to form the stable octet when forming an ionic bond, resulting in a net charge of +2. Because they’re trying to get rid of those electrons to get to the stable octet, it’s easy to remove them - this means that the ionization energy of these elements is relatively low. Finally, since they’re looking to get rid of electrons, they certainly aren’t trying to gain any, meaning that their electronegativity is relatively low.
The correct answers are A and D.