Which substances have /_\hf = 0 kj/mol by definition? select all that apply. o2(g) n(g) h2o(l) br2(l) fe(s) he(g) s6(s)

The substances that have a standard enthalpy of formation equal to 0 kJ/mol are:

We want to know which substances have a standard enthalpy of formation (ΔH°f) equal to 0 kJ/mol.

The standard enthalpy of formation is defined as the change in enthalpy when one mole of a substance in the standard state is formed from its pure elements under the same conditions.

By definition, the standard enthalpy of formation of pure elements in the standard state is zero.

Let's consider which of the following substances have a standard enthalpy of formation equal to 0 kJ/mol.

The substances that have a standard enthalpy of formation equal to 0 kJ/mol are:

Learn more about standard enthalpy of formation here: link

look at the !

pleaze mark brainliest!

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j