Identify the types of scientific investigations described. has a control group!
does not have a hypothesis
compares two or more objects
involves a test to gather evidence that supports or refutes a hypothesis
involves observations only

The answer is b i think

Idon't know hope someone you

The answer is c.  h+  and oh−  react to form water (h2o). i just took the test and i got it right. hope this !

  the volume of  0.220 m k2s    solution  required  to  completely  react with 175 ml  of 0.115m co(no3)2  calculate the moles  of co(no3)2 =  molarity x volume/1000175 x0.115/1000= 0.02  moleswrite  the reacting  equationk2s(aq)  +  co(no3)2  = 2 kno3(aq)  + cos(s)by  use  of mole ratio between k2s to co(no3)2 which  is  1: 1 the moles of k2s is therefore = 175  x0.115/1000= 0.02  molesvolume = moles/molarity=0.02/0.22=0.09  ml  of k2s