Which of these statements are true? Select all that apply. The Delta. Hf for Br2(I) is 0 kJ/mol. The Delta. Hf for He(I) is 0 kJ/mol. The Delta. Hf for Hg(I) is 0 kJ/mol. The Delta. Hf for Cl2(g) is 0 kJ/mol. The Delta. Hf for N2(I) is 0 kJ/mol. CORRECT ANSWER IS A, C, AND D.

The correct options are A, C and D.

Explanation:

Enthalpy of formation is defined as the change in the enthalpy when 1 mole of a chemical substance is formed from its pure element at standard conditions. It is represented by the symbol

Enthalpy of formation for elemental atoms is always equal to 0.

We know:

Bromine (Br) exists in a liquid state.

Helium (He) exists in a gaseous state.

Mercury (Hg) exists in a liquid state.

Chlorine (Cl) exists in a gaseous state.

Nitrogen (N) exists in a gaseous state.

For the given options:

The for will be equal to 0 because they are formed by the natural states of their elemental atoms.

Hence, the correct options are A, C and D.

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