Chromatography

Two or more substances that are mixed together but not chemically combined is a ___

• compound
• mixture
• keratin
• chromatography

chromatography separates the mixture of dyes on the basis of their ----------------------------

• density
• solubility
• gravity
• boiling point

Ink can be separated by a method of -----------------------------------------------

• distillation

• filtration

• chromatography

• sedimentation

Two or more substances that are chemically combined is a ___

• compound
• mixture
• solvent
• solute

Tags

NGSS.MS-PS1-1

A pure substance shows ------------------ spot on chromat gram

• 0
• 1
• 2
• 3

The diagram below shows a chromatogram obtained when a sample X was analysed together with four other known dyes P, Q, R and S. Dye Q was known to cause cancer. Which of the following dye(s) is/are safe for use?

• P only
• S only
• P and S
• P and X

Tags

NGSS.HS-PS1-2

A student extracts the colour from some green smarties and uses paper chromatography to separate components colours. She finds blue has a R_f =0.38 and yellow R_f =0.75 this suggests 

• the yellow is more strongly adsorbed onto the stationary phase and is less solublein the mobile phase.
• the yellow is more strongly adsorbed onto the stationary phase and is more soluble in the mobile phase.
• the blue is more strongly adsorbed onto the stationary phase and is less solublein the mobile phase.
• the blue is more strongly adsorbed onto the stationary phase and is less solublein the mobile phase.

A high R_f value indicates strong

• strong affinity to the stationary phase
• strong affinity to the mobile phase
• no affinity to the stationary phase
•  no affinity to the stationary phase

A low retention time indicates

• a high affinity to the mobile phase
• a low affinity to the stationary phase
• a high solubility in the mobile phase
• all of the above

The R_f value  for the blue component is 

• 0.3
• 0.7
• 10
• 3