C12 - experimental techniques Flashcards
(40 cards)
What is an independent variable?
A variable that is deliberately changed during the investigation.
What is a dependent variable?
A variable that is measured during the investigation.
What are control variables?
Factors that are kept constant during the experiment.
Why are SI units important?
They ensure consistent measurements worldwide.
What is the SI unit for volume?
Litre (L) or dm³
What apparatus is used for accurate volume transfer?
Pipette
What apparatus measures variable volumes accurately?
Burette
What apparatus is used to measure gas volume?
Gas syringe
What is the difference between accuracy and precision?
Accuracy is closeness to true value; precision is closeness of repeated values to each other.
What is a solute?
The substance that is dissolved.
What is a solvent?
The substance that does the dissolving.
What is a solution?
A mixture where a solute is dissolved in a solvent.
What is a saturated solution?
A solution where no more solute can dissolve.
What is concentration measured in?
mol/dm³
How does temperature affect solubility?
Higher temperature increases solubility.
What is a titration?
A method to determine the concentration of an unknown solution using a known one.
What equipment is essential for titration?
Burette and pipette
What is the end point of a titration?
The point at which neutralization is complete, shown by an indicator.
What is a concordant titre?
Titre values within ±0.10 cm³ of each other.
What is chromatography used for?
To separate and identify substances in a mixture.
What is the mobile phase in paper chromatography?
The solvent
What is the stationary phase in paper chromatography?
The filter paper
How is Rf value calculated?
Rf = distance moved by substance ÷ distance moved by solvent
What does a pure substance show on a chromatogram?
One spot
