Chemistry Flashcards
Which ion makes solutions acidic
Hydrogen ion
H+ (aq)
Describe how to test a solution to show it is acidic
Add universal indicator to the solution, it will turn red/orange/yellow
How does the pH of an acidic solution change if it becomes less acidic
The pH will increase
What type of chemical reaction occurs when a metal hydroxide is added to an acid
Neutralisation reaction
Which equation is used to work out the concentration solution in g/dm3
Concentration (g/dm3) =mass (g)/ volume (dm3)
How do you convert a volume in cm3 to a volume in dm3
Divide by 1000
Any method should identify key variables and what equipment you will use to measure the variables. What are the three key variables in an investigation
INDEPENDENT VARIABLE ( the variable we change and select different values of)
DEPENDENT VARIABLE (the variable we measure and record in a results table)
CONTROL VARIABLE (the variable we measure and meet the same throughout the investigation)
Which piece of equipment would you use to measure the mass of a chemical
Top pan balance
Which piece of equipment would you use to measure put a volume of gas produced in an experiment
Measuring cylinder
Which piece of equipment can you use to record the volume of gas produced in an experiment
Gas syringe
What observation can be made when hot sodium burns in oxygen gas
Yellow flame
White smoke
White powder left at the end of the
What is the order of discovery of the electron, proton and neutron
- Electron
- Proton
- Neutron
How do you work out the number of neutrons in an atom from the mass number and atomic number
Mass number minus atomic number
How can you calculate the relative atomic mass of an element from the mass numbers and percentage abundance of its isotopes
Mass number X percentage abundance
Divided by 100
Explain why solid sodium chloride does not conduct electricity
Ions are not free to move
What can we do to solid sodium chloride to allow it to conduct electricity
Dissolve in water to make a solution
Melt the solid
What element is used to make inherit electrodes in electrolysis
Carbon
What is the half equation to produce chlorine during electrolysis
2Cl- (arrow) Cl2 + 2e-
What ions are present in sodium chloride solution
Sodium ions (Na+), chloride ions (Cl-), hydrogen ions (H+), hydroxide ions (OH-)
What products are produced when sodium chloride solution is electrolysed
positive electrode: CHLORINE GAS
negative electrode: HYDROGEN
sodium ions join with hydroxide ions to form an alkaline solution of sodium hydroxide
How do you work out the number of moles of a substance from its mass and relative formula mass (Mr)
Moles= mass (g)/Mr
Which structures contain hexagonal rings
Graphite
Fullerenes
Graphene
Why do metals allow the conduction of thermal energy
Delocalised electrons move through the structure and transfer energy
Explain why ionic compounds like metal oxides have high melting points
Giant structure
Lots of strong forces of attraction between
oppositely charged ions
Lots of energy to break lots of bonds
Why do simple covalent bonds molecules have low melting points
Made of small molecules
Weak forces between the molecules
Little energy needed to break the weak forces
