Answer:
Rb+
Explanation:
Since they are telling us that the equivalence point was reached after 17.0 mL of 2.5 M HCl were added , we can calculate the number of moles of HCl which neutralized our unknown hydroxide.
Now all the choices for the metal cation are monovalent, therefore the general formula for our unknown is XOH and we know the reaction is 1 equivalent acid to 1 equivalent base. Thus we have the number of moles, n, of XOH and from the relation n = M/MW we can calculate the molecular weight of XOH.
Thus our calculations are:
V = 17.0 mL x 1 L / 1000 mL = 0.017 L
2.5 M HCl x 0.017 L = 2.5 mol/ L x 0.017 L = 0.0425 mol
0.0425 mol = 4.36 g/ MW XOH
MW of XOH = (atomic weight of X + 16 + 1)
so solving the above equation we get:
0.0425 = 4.36 / (X + 17 )
0.7225 +0.0425X = 4.36
0.0425X = 4.36 -0.7225 = 3.6375
X = 3.6375/0.0425 = 85.59
The unknown alkali is Rb which has an atomic weight of 85.47 g/mol
Molar mass :
Cl₂ = 71.0 g/mol Na = 23.0 g/mol
<span>2 Na + Cl</span>₂<span> = 2 NaCl
</span>
2 x 23 g Na -------> 71.0 g Cl₂
96.6 g Na ----------> ?
Mass Cl₂ = ( 96.6 x 71.0 ) / ( 2 x 23 )
Mass Cl₂ = 6858.6 / 46
= 149.1 g of Cl₂
hope this helps!
Answer:
Oxygen and Chlorine
Explanation:
Covalent bonds involve the sharing of electrons between nonmetals.
Transition metals are less reactive than alkali metals because of their high ionization potential and high melting point.
On moving from left to right of the periodic table for every period, electrons fill in the same shell or orbital, with the alkali metals having the least filled outermost shells, one electron, which equates to fewer protons in them.
Consequently, they have a lesser attraction power from the nucleus, whereas, the corresponding transition metals of the same period have more protons interacting with electrons at the same distance, far from the nucleus as the alkali metals.
