First, We have to write the equation for neutralization:
Ba(OH)2 + 2HCl → BaCl2 + 2H2O
so, from the equation of neutralization, we can get the ratio between Ba(OH)2 and HCl. Ba(OH)2 : HCl = 1:2
- We have to get the no.of moles of Ba(OH)2 to do the neutralization as we have 25.9ml of 3.4 x 10^-3 M Ba(OH)2.
So no.of moles of Ba(OH)2 = (25.9ml/1000) * 3.4x10^-3 = 8.8 x 10^-5 mol
and when Ba(OH)2 : HCl = 1: 2
So the no.of moles of HCl = 2 * ( 8.8x10^-5) = 1.76 x 10^-4 mol
So when we have 1.76X10^-4 Mol in 16.6 ml (and we need to get it per liter)
∴ the molarity = no.of moles / mass weight
= (1.76 x 10^-4 / 16.6ml)* (1000ml/L) = 0.0106 M Hcl
Answer:

Explanation:
<u>Given Data:</u>
Volume = v = 1.12 dm³ = 1.12 L
Density of nitrogen at STP = D = 1.25 g / L
Molar mass = M = 14 * 2 = 28 g / mol
Avogadro's Number =
= 6.023 * 10²³ mol⁻¹
<u>Required:</u>
No. of molecules = ?
<u>Formula:</u>

<u>Solution:</u>
No. of molecules = (1.25*1.12) / 28 * (6.023 * 10²³)
No. of molecules = ( 1.4 / 28 ) * 6.023 * 10²³
No. of molecules = 0.05 * 6.023 * 10²³
No. of molecules = 0.3 * 10²³
No. of molecules = 3 * 10²² molecules
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Hope this helped!
<h3>~AH1807</h3>
The answer is Ra
Atomic number for Be is 4
Atomic number for Mg 12
Atomic number for Ra 88
Atomic number for Ba 56