Answer:
37.3
263.5
Explanation:
The scale measures hundreds of units, tens of units, units, and parts of units (1 decimal place.
Scale 1
Hundreds 0 * 100 = 0
Tens: 3 * 10 = 30
Units: 7 * 1 = 7
1/10 unit = 3* 0.1 = 0.3
Total 30 + 7 + 0.3 = 37.3
Scale 2
Hundreds 2 * 100 = 200
Tens: 6 * 10 = 60
Units: 3 * 1 = 3
1/10 unit = 5* 0.1 = 0.5
Total = 200 + 60 + 3 + 0.5 = 263.5
The Relative Formula Mass of NaH2PO4 is 120 g/mol
Therefore, the number of moles = 6.6/120
= 0.055 moles of NaH2PO4 which is also equal to the number of moles of H2PO4.
[H2PO4-] = Number of moles oof H2PO4-/Volume of the solution in L
= 0.055/ ( 355 ×10^-3)
= 0.155 M
Na2HPO4 undergoes complete dissociation as follows;
Na2HPO4 (aq)= 2Na+ (aq) + HPO4^2- (aq)
1 mole of Na2HPO4 = 142 g/mol
Therefore; number of moles = 8.0/142
= 0.0563 moles
[HPO4 ^-2] is given by no of moles HPO4^2- /volume of the solution in L
= 0.0563/(355×10^-3)
= 0.1586 M
Both H2PO4^2- and HPO4^2- are weak acids the undergoes partial dissociation
Ka of H2PO4- = 6.20 × 10^-8
[H+] =Ka*([H2PO4-]/[HPO4(2-)]
= (6.20 ×10^-8)×(0.155/0.1586)
= 6.059 ×10^-8 M
pH = - log[H+]
= - log (6.059×10^-8)
= 7.218
PH = -log [H3O+]
4.15 = -log [H3O+]
[H3O+] = 10^(-4.15)
[H3O+]= 7.08 × 10^-5
Answer:
2NO(g) + O2(g) ---> 2NO2(g)
Explanation:
The mechanism for this reaction involves two elementary reactions in which both are bimolecular as shown below;
NO(g) +O2(g) ----> NO2(g) + O(g)
NO(g) + O(g) ----> NO2(g)
Hence overall balanced reaction equation;
2NO(g) + O2(g) ---> 2NO2(g)
