A Recognize a problem C. Test the hypothesis with an experiment B Form a hypothesis D. Draw conclusions 1 Dana wanted to know how synthetic fibers were different from natural fibers. 2 Angela’s experiment proved that earthworms move away from light. 3 Scott said, “If acid rain affects plants in a particular lake, it might affect small animals such as crayfish, that live in the same water.” 4 Michael fed different diets to three groups of guinea pigs. His experiment showed that guinea pigs need vitamin C and protein in their diets. 5 Kim’s experiment showed that chicken egg shells were stronger when she gave the hen food to which extra calcium had been added.

where's the diagram?

the answer is 75.0%.

answer: - first one is the correct answer. .

explanations: - potassium sulfide is and cobalt(ii) chloride is .

charge on k is +1, charge on s is -2, charge on co is +2 and charge on cl is -1.

in a double replacement reaction the ion exchange takes place. in general the reaction looks like:

if one of the product is insoluble as per solubility rules then a precipitate of it is formed.

when we mix the aqueous solutions of potassium sulfide and cobalt(ii) chloride then chloride ion goes with potassium ion and sulfide ion goes with cobalt ion and the balanced equation is written as:

k and cl has equal charges, similarly co and s has equal charges and hence no subscripts are used for the product side.

as per the solubility rules, cos is insoluble and so it's precipitate is formed.

looking at the given choices, first choice is correct.