Topic 7- Rates of reaction Flashcards
Core Practical: measuring gas production (in the reaction between hydrochloric acid and marble chips)
Mass loss
-Place concile flask on weighing scale with HCI
-Add marble chips container on weighing scale
-Set scale to zero
-Add marble chips
-Quickly place cotton wool
-Record initial mass
-Record mass drop every 10 seconds
Gas will flow out of the cotton wool cuasing mass change
Why is cotton wool used in the gas production experiment?
-Prevents spitting
-Allows gas to escape
Core Practical: measuring gas production (in the reaction between hydrochloric acid and marble chips)
Water displacement
-Place bung on measuring cylinder full of water
-Place measuring cylinder upside in water
-Attach to clamp and remove bung
-Insert end of delivery tube into measuring cylinder
-Add marble chips
-Add bung to conicle flask with HCL
-Start timer (when first bubble in measuring cylinder)
-Measure gas volume every 30 seconds (water displaced)
What other equipment can be used to find gas production?
Gas syringe
Core Practical: observing a colour change (in the reaction between sodium
thiosulfate and hydrochloric acid)
-Place cross under conicle flask
-Add 50 cm^3 Sodium Thiosulfate to flask
-Add 10cm^3 HCI
-Time how long it takes to be cloudy
-Repeat using lower concentration of Sodium Thiosulfate (40 sm^3 and adding rest with distilled water)
What does sodium thiosulfate and hydruachloric acid produce?
Sodium chloride+ Sulfur Dioxide+ Water+Sulfur
Why dopes sulfur make it cloudy?
-Insoluable
-its a Precipitate
What three things can be measured to find the rate of reaction?
-Mass change
-Gas produced (volume)
-Light passing through
How do reactions occur?
-Particles collide with enough energy to react
How to increase rate of reaction?
-Higher SA:V
-Higher concentrations
-Higher temperature
-Add a catalyst
How does higher SA:V quicken reaction?
-More particles able to collide
-(Not hidden behind other particles)
How does higher higher concentration quicken reaction?
-More particles to collide
How does higher temperature quicken reaction?
-More energy
-Faster particles
-More energetic collisions
more energetic
meaning more likely to cuase a reaction
What is a catalyst?
-A substance that increases a rate of reaction without being chemically changed or used up
How do catalysts lower the quicken the rate of reaction?
-Lower the amount of activation energy needed
