Determine whether or not the mixing of each pair of solutions results in a buffer. show all work!
a.) 75.0 ml of 0.10 m hf ; 55.0 ml of 0.15 m naf
b.) 150.0 ml of 0.10 m hf ; 135.0 ml of 0.175 m hcl
c.) 165.0 ml of 0.10 m hf ; 135.0 ml of 0.050 m koh
d.) 125.0 ml of 0.15 m ch3nh2 ; 120.0 ml of 0.25 m ch3nh3cl
e.) 105.0 ml of 0.15 m ch3nh2 ; 95.0 ml of 0.10 m hcl

a) Acidic buffer

b) No buffer

c) Acidic buffer

d) Basic buffer

e) Basic buffer

Explanation:

a) 75.0 mL of 0.10 M HF ; 55.0 mL of 0.15 M NaF -Acidic buffer

Mixing of 75.0 mL of 0.10 HF and 55.0 mL of 0.15 mL NaF results in acidic buffer. HF/NaF is a buffer of weak acid and its conjugate base. F- is the conjugate base of acid,HF.

b.) 150.0 mL of 0.10 M HF ; 135.0 mL of 0.175 M HCl-No buffer

Mixing HF and HCl will not results in a buffer. Both are acids, and no conjugate base is present.

c.) 165.0 mL of 0.10 M HF ; 135.0 mL of 0.050 M KOH-Acidic buffer

HF reacts with KOH to form KF. F- is a conjujate base of HF. As volume and concentration of HF is more than KOH, therefore, HF will remain after reaction with KOH. HF/KF will be a buffer of weak acid and its conjugate base.

d.) 125.0 mL of 0.15 M CH3NH2 ; 120.0 mL of 0.25 M CH3NH3Cl -Basic buffer

CH3NH2/CH3NH3+ is a buffer of weak base and its conjugate acid.

e.) 105.0 mL of 0.15 M CH3NH2 ; 95.0 mL of 0.10 M HCl-Basic buffer

CH3NH2 is a weak base and HCl is a strong acid. CH3NH2 reacts with HCl to form its conjugate acid CH3NH3+. Volume and concentration of CH3NH2 is more as compared to HCl and hence, will remain in the soution after reactionf with HCl.

CH3NH3+/CH3NH2 is a buffer of weak base and its conjugate acid.

atomic number of carbon is 6

electronic configuration of carbon is 1s²2s²2p²

orbital diagram of carbon is as shown here in the image.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.