When is it necessary for a scientists to do research?

select all that apply.

a. before forming a hypothesis

b. only after a hypothesis is written

c. after generating an idea from an observation

d. when designing an experiment to test a hypothesis

A. before forming a hypothesis

C. after generating an idea from an observation

D. when designing an experiment to test a hypothesis

Explanation:

A. before forming a hypothesis: A background research of the previous research studies as well as the literature review is to be done before constructing a hypothesis.

C. after generating an idea from an observation:  After generating an idea from the observation other methodology should be implemented so as to rectified the fact that the observation is correct.

D. when designing an experiment to test a hypothesis: While implementing a suitable scientific methodology a research is required to be done so as test the hypothesis by an accurate and valid procedure.  

adding or remove a gaseous reactant or product changes the concentrations. if the concentration of reactant or product is increased, the system will shift away from the side in which concentration was increased (i.e. if the concentration of reactants is increased, the system will shift toward the products. if more products are added, the system will shift to form more reactants). conversely, if the concentration of reactant or product is decreased, the system will shift toward the side in which concentration was decreased (i.e. if reactants are removed, the system will shift to form more reactants. if the concentration of products is decreased, the equilibrium will shift toward the products).

explanation:

nacl is added to the aqueous of what? ? in order to get a proper answer you have to specify the exact composition of the aqueous solution.