Bronsted-Lowry acid/base and conjugate acid/base. Please and thank you. 1. HF(aq)+ H2O(l)⇌H3O^+(aq)+F^−(aq)
2. NH3(aq)+H2O(l)⇌NH4^+(aq)+OH^−(aq)
3. HNO3(aq)+ H2O(l)→H3O+(aq)+NO3^−(aq)
4. C4H9N(aq)+H2O(l)⇌C4H9NH^+(aq)+OH^−( aq)

1.

HF --> B.L. Acid (gave away a proton)

F~ --> Conjugate Base (Acid becomes conj. base after losing a proton)

H2O --> B. L. Base (accepted the proton of HF)

H3O+ --> Conjugate Acid (Base becomes conj. acid after accepting a proton)

2.

NH3 --> B. L. Base (accepted a proton)

NH4+ --> Conjugate Acid

H2O --> B. L. Acid (gave away a proton)

H3O+ --> Conjugate Base (Acid becomes conj. base after losing a proton)

3.

HNO3 --> B.L. Acid

NO3~ --> Conjugate Base

H2O --> B. L. Base

H3O+ --> Conjugate Acid

4.

C4H9N --> B. L. Base

C4H9NH+ --> Conjugate Acid

H2O --> B. L. Acid

OH~ --> Conjugate Base

that's what i got you can count the number of atoms

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3