Which scenario represents a scientific investigation

a. a measurement of growth patterns of crystals in space

b. a selection of favorite songs in a survey

c. a questionnaire on the quality of care in a hospital

d. a survey on the best options for reducing air pollution

I would think it is a. A measurement of growth patterns of crystals in space

That is something that is being tested the other ones are just questions and surveys .

14 days is the half-life of phosphorus-32

consider the reaction below.

 no rx

at 500 k, the reaction is at equilibrium with the following concentrations.

[pci5]= 0.0095 m

[pci3] = 0.020

[ci2] = 0.020 m

what is the equilibrium constant for the given reaction?

0.042

0.42

2.4

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