P1 Flashcards
(26 cards)
Define exothermic
A reaction where heat is given out
Define endothermic
A reaction where heat is absorbed (in)
What does an exothermic reaction show in the rate of reaction?
An increase of temperature in the reaction
What does an endothermic reaction show in the rate of a reaction?
A decrease of temperature in the reaction
Define activation energy
The minimum amount of energy required for a chemical reaction to take place
Does a catalyst increase OR decrease the rate of a reaction AND why?
Increase
WHY? Because it lowers activation energy
What is the role of a catalyst?
Catalysts provide an alternative pathway in a reaction
Is the energy change in an endothermic reaction positive OR negative?
Positive
Is the energy change in an exothermic reaction positive OR negative?
Negative
What is the aim of the required practical in C5?
To investigate variables that affect temperature changes in reacting solutions
Describe the method of the C5 required practical - exothermic and endothermic reactions
- Gather equipment
- Place the polystyrene cup inside the beaker. (This prevents the cup from falling over.)
- Using a measuring cylinder, measure 30cm^3 of acid. Pour this into the polystyrene cup
- Record the temperature of the acid using a thermometer
- Using a top pan balance, measure the appropriate amount of solid.
- Add the solid to the acid and record the temperature of the acid each minute for 10 minutes.
What is the difference between a compound and a mixture?
A compound is two or more elements chemically combined whereas a mixture is two or more substances not chemically combined.
What is the name of the pattern formed from carrying out paper chromotography?
Chromatogram
Which method of separation is useful to separate an insoluble solid from a liquid?
Filtration
Give the name of a method to separate a soluble solid from a liquid.
Evaporation
Which method of distillation would you use to separate liquids with similar boiling points?
Fractional distillation
Who discovered that the plum pudding model was wrong?
Ernest Rutherford
Who first devised an experiment that proved the existence of the neutron?
James Chadwick
What is the electronic structure of sodium?
2,8,1
Why did Mendeleev leave gaps in his table of elements?
Some elements had not been discovered yet
How are the group number and the number of electrons in the outer shell of an element related?
The group number is the number of electrons in the outer shell
What kind of ions do metals form?
Positive ions - cations.
State 3 trends as you go down Group 1
- reactivity increases
- atomic size increases
- melting and boiling points decrease
How do the boiling points of halogens change as you go down the group from fluorine to astatine?
As you go down the halogens from fluorine to astatine, the boiling points increase
