Identify all statements are true
1. zeroth order rate constants have units of inverse seconds
2. first order reactions have half lives that are dependent on time
3. catalysts cannot appear in the rate law for a reaction.

1. False

2. False

3. True

Explanation:

Identify all statements are true

1. zeroth order rate constants have units of inverse seconds. FALSE.

The rate law for a zeroth order rate reaction has the following form:

r = k

where,

r is the rate of the reaction

k is the rate constant

k has the same units than r, that is, M . s⁻¹.

2. first order reactions have half lives that are dependent on time . FALSE.

Half-life (t1/2) of a first order reaction can be calculated using the following expression.

As we can see, half-life does not depend on time.

3. catalysts cannot appear in the rate law for a reaction. TRUE.

The rate law has the following form:

r = k . [A]ᵃ . [B]ᵇ

where,

[A] and [B] are the concentrations of the reactants

a and b are the reaction orders

Catalysts do not appear in the rate law.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.