Experimental Techniques And Chemical Analysis Questions Flashcards
What is the difference between a physical change and a chemical change?
A physical change alters the form or appearance of a substance without changing its chemical composition, while a chemical change results in the formation of new substances with different chemical properties.
Name appropriate apparatus used to measure time.
Stopwatch.
Name appropriate apparatus used to measure temperature.
Thermometer.
Name appropriate apparatus used to measure mass.
Balance.
Name a piece of apparatus used to measure volume precisely.
Burette.
What is a solvent?
A solvent is a substance that dissolves a solute.
What is a solute?
A solute is a substance that is dissolved in a solvent.
Define a solution.
A solution is a mixture of one or more solutes dissolved in a solvent.
What is a saturated solution?
A saturated solution contains the maximum concentration of a solute dissolved in the solvent at a specified temperature.
Define residue.
Residue is the solid substance that remains after processes like evaporation, distillation, or filtration.
What is filtrate?
Filtrate is the liquid or solution that has passed through a filter.
Name a method of separation and purification using a suitable solvent.
Solvent extraction.
Describe the process of filtration.
Filtration is a method used to separate solid particles from liquids or gases using a filter that allows only the fluid to pass through.
What is crystallization?
Crystallization is a technique used to separate and purify a solid from a solution, where the solid forms crystals as the solution cools or evaporates.
Describe simple distillation.
Simple distillation is a method used to separate a liquid from a solution by heating it to create vapor and then cooling the vapor to obtain the liquid.
What is fractional distillation?
Fractional distillation is a separation technique used to separate mixtures of liquids with different boiling points.
How can you assess the purity of a substance?
By comparing its melting point or boiling point to known values; pure substances have sharp melting and boiling points, while impure substances have a range.
How is paper chromatography used to separate mixtures?
Paper chromatography separates mixtures of soluble colored substances by allowing them to move with a solvent through a piece of paper.
How can you identify unknown substances using chromatography?
By comparing the Rf values of the unknown substances with those of known substances.
State the Rf equation.
Rf = distance travelled by substance / distance travelled by solvent.
