How do I determine the Rf Value with just the information I have provided? As for the Ion, are they looking for a poistive or negative answer? Rf= distance traveled by component/distance traveled by the solvent I just took a piece out of my homework so I can complete the rest Hopefully I will learn and then know what I am doing. Results Data Table for Unknown A Distance Solvent Traveled (cm) 7.0 Spot Color Distance Traveled (cm) 1.3 *Rf Calculated lon Present Unknown A Component 1 Unknown A Component 2 Brown with light spots Brown with light spots 4.6 4.9 Unknown A Component 3 Brown with light spots Solution For unknown A component 1: R f = (1.3 cm) / (7.0 cm) = 0.186 or 0.19 For unknown A component 2: R f = (4.6 cm) / (7.0 cm) = 0.657 or 0.66 For unknown A component 3: R f = (4.9 cm) / (7.0 cm) = 0.7 For the \'ion present\' column, it is being asked what ion is present in the unknown A which is determined by referencing to the R f values of the known compound and it\'s components. For example, first you are given a known compound having a ion (say given compound is NaCl which we know it contains Na + ions). Now paper chromatography for NaCl is done and R f values are calculated & noted for Na + ion. Now in second experiment you are given an unknown compound and you perform the paper chromatography and calculate the R f values. If R f value of Na + (from first experiment of known) matches with the R f value of unknown (from second experiment) then we can say that unknown compound contains Na + . This Na + is the ion which is being asked as \'ion present\'. .