C2 Experimental Techniques

Question 1

what is used to measure time and what is the unit

Answer 1

stopwatch/seconds

Question 2

what is used to measure temperature and what is the unit

Answer 2

thermometer/degrees celsius

Question 3

what is used to measure mass and what is the unit

Answer 3

Mass balance/grams

Question 4

3 pieces of equipment to measure volume of a liquid and what is the unit

Answer 4

measuring cylinder, volumetric pipette, burette/ cm³

Question 5

what is used to measure volume of a gas and what is the unit

Answer 5

gas syringe/cm³

Question 6

what process is used to separate two or more solids that are soluble

Answer 6

paper chromatography

Question 7

how to calculate the Rf value in paper chromatography

Answer 7

distance moved by solute/distance moved by solvent

Question 8

define pure substance

Answer 8

a substance which contains single element or compound not mixed with any other substance

Question 9

describe 3 ways that the purity of a substance can be assessed

Answer 9

melting point, boiling point, chromatography

Question 10

describe how chromatography can be used to assess purity

Answer 10

a pure substance will only produce one well defined spot on a chromatogram

Question 11

what is a solute

Answer 11

substance that is dissolved in a solvent

Question 12

what is a solvent

Answer 12

substance that dissolves a solute

Question 13

what is a solution

Answer 13

a liquid mixture (solute + solvent)

Question 14

define volatility

Answer 14

how easily a substance evaporates

Question 15

define solubility

Answer 15

how easily substance dissolves

Question 16

what is crystallization

Answer 16

when a liquid that contains a dissolved salt is evaporated to leave the salt behind

Question 17

how do you extract a pure sample from a chromatogram

Answer 17

1. isolate the substance you want to extract
2. dissolve it in a water to remove any insoluble material
3. evaporate the water in a dry place