In: Chemistry
in a test tube containing 2 mL of 2.4*10^-4 M KSCN, and 23 mL of 0.10 M Fe(NO3)3, what are the number of moles of SCN^-, the number of moles of FeSCN^2+, and the concentration of FeSCN^2+ in mol/L?
2 mL of 2.4*10^-4 M KSCN,
no of moles of KSCN = molarity * volume in L
= 2.4*10-4 *0.002
= 4.8*10-7 moles
KSCN -----> K+ + SCN-
4..8*10-7 moles 4.8*10-7 moles
23 mL of 0.10 M Fe(NO3)3
no of moles of Fe(NO3)3 = molarity *volume in L
= 0.1*0.023 =0.0023 moles
Fe(NO3)3 ------> Fe+3 + 3NO3-
0.0023 moles 0.0023 moles
Fe+3 + SCN- -----> FeSCN^2+
SCN- is limiting reageent
1 mole of Fe3+ react with SCN- to form 1 mole of FeSCN^2+
4.8*10-7 moles of Fe3+ react with SCN- to form 4.8*10-7 moles of FeSCN^2+
total volume is = 2+23 = 25 ml = 0.025 L
molarity of FeSCN^2+ = no of moles/ volume in L
= 4.8*10-7/0.025 = 1.92*10-5 M