Summer Assessment 3- more Flashcards
how can you work out the speed of a reaction on a graph
- by recording the amount of product formed or the amount of reactant used up over time
- the steeper the line on a graph the fatser the reaction
- line becomes less steep as reactants are used up
what do the quickest reactions show on a graph
-they have the steepest line and become flat in the least time
what does the rate of a chemical reaction depend on
- collision frequency of reacting particles- the more collisions the faster the reaction
- energy transferred during a collision
what is activation energy
-the minimum amount of energy particles need to react
why to particles need activation energy
-to break the bonds in reactants to start to the reaction
explain the method you would carry out to measure how surface area affects rate
- use marble chips and HCL
- set up the apparatus so you have a conical flask with marble chips in it as well as HCL- attach to the bung in the conical flask a gas syringe
- measure volume of gas produced using a gas syringe
- take readings at regular intervals and record the results
why does using finer particles of solid mean a higher rate of reaction
-as finer particles mean the marble has a larger surface area
what effect does changing the concentration of acid have on the rate of reaction
a higher concentration gives a faster reaction
what is the general formula for alkenes
CnH2n
what is the empirical formula (for ethene)
CH2
-simplest ratio of atoms
what is the molecular formula (for ethene)
C2H4
-actual number of atoms of each element in a molecule
what is the structural formula (for ethene)
CH2CH2
-shows arrangement of atoms carbon by carbon
what is a homologous series
-a group of compounds that can all be represented by the same general formula
what is a functional group
- a group of atoms that determine how a compound typically reacts
definition of isomer
two or more molecules with the same molecular formulae but different structural formula
what can you infer from differently shaped carbon chains
- these isomers have similar chemical properties
- but different physical properties due to the change in shape of the molecules
what could you infer from functional groups being in different places
-these isomers have different physical properties
what could you infer from functional groups being different
-these isomers have different physical and chemical properties
What is a hydrocarbon?
a compound of hydrogen and carbon only
What happens when you burn a fuel?
releases energy in form of heat
What is burning a fuel also known as?
-combustion reaction