Ineed i dont get it first question

Refinement

Explanation:

The 3R's policy was fundamentally introduced to safeguard the animals from harsh experiments which could change their mental and physical abilities and lead to their extinction one day.

The principles of 3R's (Replacement , Reduction and Refinement) were developed long time ago. It is an strategy to perform more Humane animal research.

These are defined as,

Replacement is a method to avoid or replace the uses of animals.

Reduction is a method to minimize the number of animals used every experiment.

Refinement is a method of minimizing animal suffering and improving welfare.

elements

explanation:

yes the other ones are right just show me a pic of ur face cuz u look hot

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.