Shared Flashcard Set

Details

Unit 1 flashcards
^
37
Chemistry
11th Grade
04/15/2014

Additional Chemistry Flashcards

 


 

Cards

Term
What equation do you use to work out the rate of a reaction if it has a distinct end?
Definition

Rate = 1/time

Term
What two things are needed for a reaction to take place?
Definition

-energy above the activation energy 


-collision of particles at the correct angle or orientation

Term
What is Activation Energy?
Definition

the minimum amount of energy required for a reaction

Term
What is the activated complex?
Definition

the unstable intermediate between reactants and products containing partial bonds

Term
How do you calculate the enthalpy change of a reaction?
Definition

HP- HR

(enthalpy of products - enthalpy of reactants)

Term
What do catalysts do?
Definition

Catalysts lower the activation energy increasing the number of particles able to react

Term
How do Heterogeneous catalysts work?
Definition

They work by adsorbing reactants onto active sites which weakens their bonds.

Term
How does poisoning of catalysts occur?
Definition

Poisoning occurs when chemicals are absorbed onto active sites stopping them working

Term
How can enzymes be denatured?
Definition

 Enzymes can be denatured if the pH, temperature or alcohol content is too extreme

Term

Define each component /\H=cm/\T

                      

Definition

ΔH is enthalpy change

c is 4.18 Kj/mol

m is number of kilograms (litres) of water

ΔT is the temperature change

Term
What step comes after working out the energy change for a certain mass of compound reacting?
Definition

work out how much 1 mole would produce

Term
Why does atomic size increase going down a group?
Definition

there is an extra energy level moving the electrons further from the nucleus thus increasing the size

Term
Why does ionisation energy increase across a period?
Definition

It increases across a period as the electrons are closer to the nucleus therefore harder to remove

Term
Why does ionisation energy decrease down a group?
Definition

It decreases down a group as the electrons are further from the nucleus and shielded from its pull by the inner electrons

Term
Why is there a large jump between the first and second ionisation energies?
Definition

There is a large jump between the first and second ionisation energies for group 1 metals as you are removing an electron from an energy level closer to the nucleus

Term
Why does electronegativity increase going across a period?
Definition

It increases across a period as the nuclear charge increases pulling the electrons closer

Term
Why does electronegativity decrease down a group?
Definition

It decreases down a group as the pull of the nucleus is being shielded by the inner electrons

Term
What do atoms with equal electronegativities form?
Definition

Pure covalent bonds

Term
What do atoms with different electronegativities form?
Definition

POLAR covalent bonds

Term
What are the symbols for the atoms with the biggest and lowest electronegativities?
Definition

The atoms with the biggest electronegativities have a δ-charge and those with the lowest value have a δ+ charge.

Term
Describe metallic bonding
Definition

Metallic bonds have positive cores surrounded by delocalised electrons enabling the metals to conduct.

Term
Where is metallic bonding found and is it strong?
Definition

This force of attraction is very strong and exists in metal elements.

Term
Describe Ionic bonding
Definition

Ionic bonds are an electrostatic force of attraction between oppositely charged ions.

Term
Describe ionic bonding's melting points & structure
Definition

They have high melting points and have a crystal lattice structure that must be broken before the ions are free to move and conduct electricity.

Term
Are ionic compounds soluble?
Definition

Ionic compounds are soluble in polar solvents like water

Term
Describe the strength of covalent bonds
Definition

Covalent bonds are very strong and difficult to break

Term
Describe covalent Network bonding
Definition

Covalent network substances have massive structures with millions of bonds which have to be broken to change their state

Term
What are covalent molecular's at room temp and what is broken to change their state?
Definition

•Covalent molecular substances are usually liquid or gas at room temperature.

 

 

•It is weak intermolecular forces that are broken when their state is changed

Term
How are dipole-dipole attractions caused?
Definition

Dipole –Dipole attractions are caused by molecules that have a permanent dipole

 

They are stronger than Van der Waals.

Term
Describe Van Der Waals Strength.
Definition

They are the weakest intermolecular force

Term
What will one mole of a substance contain?
Definition

6.02x1023 formula units

Term
What will one mole of a monatomic element contain?
Definition

6.02x1023 atoms

Term
What will one mole of a diatomic and covalent molecular substance contain?
Definition

6.02x1023 molecules

 

 

Term
What will one mole of Ionic compounds contain?
Definition

6.02x1023 formula units

Term
What happens to the molar volume of all gases at constant temperature and pressure?
Definition

Stays the same

Term
How do we work out volume of gases from a balances equation?
Definition

We can use simple ratios to work out the volumes of gases from a balanced equation

Supporting users have an ad free experience!