Edexcel A Level Chemistry (Paper 3)
Questions With Correct Update
what can heat help a solid do? - Correct Answer - dissolve
why should the volumetric flask be shaken when making a standard solution? - Correct
Answer - to ensure a uniform concentration
why is a volumetric pipette more accurate than a measuring cylinder? - Correct Answer
- smaller uncertainty
if the burette isn't rinsed with the substance that will be put in it, residual water might
have what effect? - Correct Answer - dilute the concentration leading to a larger titre
what is the problem with leaving the funnel in the burette? - Correct Answer - small
drops of liquid may fall from the funnel leading to a lower titre volume
why is it okay to rinse with distilled water in a titration? - Correct Answer - it doesn't add
any extra mols of reagents
what can you do to decrease apparatus uncertainties? - Correct Answer - decrease
sensitivity uncertainty by using a greater resolution or increase the size of the
measurement
how would you reduce % uncertainty in a burette? - Correct Answer - make the titre a
larger volume by increasing conc and vol of the substance in the conical flask or
decreasing the conc of the substance in the burette
how would you reduce % uncertainty in measuring mass? - Correct Answer - use a
balance that measures to more decimal places
is water a poor or good nucleophile? - Correct Answer - poor
how does water react with halogenoalkanes - Correct Answer - slowly in a substitution
reaction
why does water go in the liebig condenser from the bottom? - Correct Answer - to go
against gravity allowing more efficient cooling and preventing the backflow of water
why should electric heaters be used to heat organic substances? - Correct Answer -
highly flammable
Questions With Correct Update
what can heat help a solid do? - Correct Answer - dissolve
why should the volumetric flask be shaken when making a standard solution? - Correct
Answer - to ensure a uniform concentration
why is a volumetric pipette more accurate than a measuring cylinder? - Correct Answer
- smaller uncertainty
if the burette isn't rinsed with the substance that will be put in it, residual water might
have what effect? - Correct Answer - dilute the concentration leading to a larger titre
what is the problem with leaving the funnel in the burette? - Correct Answer - small
drops of liquid may fall from the funnel leading to a lower titre volume
why is it okay to rinse with distilled water in a titration? - Correct Answer - it doesn't add
any extra mols of reagents
what can you do to decrease apparatus uncertainties? - Correct Answer - decrease
sensitivity uncertainty by using a greater resolution or increase the size of the
measurement
how would you reduce % uncertainty in a burette? - Correct Answer - make the titre a
larger volume by increasing conc and vol of the substance in the conical flask or
decreasing the conc of the substance in the burette
how would you reduce % uncertainty in measuring mass? - Correct Answer - use a
balance that measures to more decimal places
is water a poor or good nucleophile? - Correct Answer - poor
how does water react with halogenoalkanes - Correct Answer - slowly in a substitution
reaction
why does water go in the liebig condenser from the bottom? - Correct Answer - to go
against gravity allowing more efficient cooling and preventing the backflow of water
why should electric heaters be used to heat organic substances? - Correct Answer -
highly flammable
