4:Formulae, Equations and Amount of Substance Flashcards
What is Avogadro’s constant
6.022x10^23
How do you calculate mass using moles and relative molecules mass (Mr)?
Mass = moles x Mr
What is the definition of relative atomic mass?
The mean mass of an atom of an element, divided by one twelfth of the mean mass of an atom of the carbon-12 isotope
What is the definition of relative molecular mass?
The mean mass of a molecule of a compound, divided by one twelfth of the mean mass of an atom of the carbon-12 isotope.
What is the formula for sulphuric acid?
H2SO4
What is the formula for nitric acid?
HNO3
What is the formula for phosphoric acid?
H3PO4
What is the formula for hydrogen sulfide?
H2S
What is the equation for metal + water?
Metal + Water —> Metal hydroxide + hydrogen
What is the equation for metal + acid?
Metal + Acid —> Salt + Hydrogen
What is the equation for oxide + acid?
Oxide + Acid —> Salt + Water
What is the equation for hydroxide + acid?
Hydroxide + Acid —> Salt + Water
What is the equation for carbonate + acid?
Carbonate + Acid —> Salt + Water + Carbon dioxide
What is the equation for hydrogencarbonate + acid?
Hydrogencarbonate + Acid —> Salt + Water + Carbon dioxide
What is the equation for ammonia + acid?
Ammonia + Acid —> Ammonium salt
What is the definition of a mole?
A unit used to measure the amount of a substance
What does a metal carbonate break down into?
Metal carbonate —> Metal oxide + Carbon Dioxide
What is the definition of molar mass?
A substance’s mass in grams per mole
What is the empirical formula?
The simplest whole number ratio of atoms of each element in a compound
What is the molecular formula?
The actual number of each atom in a molecule
How do you calculate the imperial formula of a compound from its compositing by using mass or percentage?
1) Mass or percentage / Ar of all elements
2) Write it’s simplest whole number ratio form
What is the ideal gas equation?
P x v = n x R x T
What is P in the ideal gas equation?
Pressure (Pa)
What is v in the ideal gas equation?
Volume (m^3)
What is n in the ideal gas equation?
Number of moles
What is R in the ideal gas equation?
Gas Constant (8.31 J mol^-1 K^-1)
What is T in the ideal gas equation?
Temperature (K)
How do you get from dm^3 to m^3?
Divide by 1000
How do you get from cm^3 to m^3?
Divide by 1x10^6
How do you get from Celsius to Kelvin?
°C + 273 = K
In the ideal gas equation what is the relationship between pressure and temperature?
Pressure is proportional to temperature
In the ideal gas equation what is the relationship between volume and temperature?
Volume is proportional to temperature
In the ideal gas equation what is the relationship between pressure and volume?
Pressure and Volume are inversely proportional
What is the equation for percentage yield?
Percentage yield = actual mass / theoretical mass
What is the equation for atom economy?
Atom economy = Mr of desired product / Mr of all reactants
How do you calculate the volume of gas in dm^3?
Volume of gas = number of moles x molar gas volume (24 at room temp)
How do you calculate the number of particles in a substance?
Number of particles = Avagadro’s constant x number of moles
How to calculate number of moles in a solution?
Number of moles = concentration x volume
What is the definition of a hazard?
Hazards are things that could cause harm to you or to others around you.
What is the definition of a risk?
The likelihood of a hazard causing harm to you or something else
What key points should a risk assessment cover?
- identification of all hazards
- the risk associated with each hazard
- the likelihood of something going wrong
- the seriousness of the risk
- how to reduce the risk
What is a standard solution?
A solution used in titration with a known concentration.
How do you make a standard solution? (C.P.)
1) Weigh out the amount of solid using a balance and a plastic weighing boat
2) Transfer the solid from the boat to a beaker and wash any solid left using deionised water
3) Dissolve the solid fully using deionised water, stir to ensure fully dissolved
4) Transfer the solution into a volumetric flask using a funnel and rinse beaker and glass rod to make sure as much of the solution is used as possible
5) Use more deionised water to fill to the graduation line
6) Invert the flask a few times
What colour does phenolphthalein turn in an acid?
Colourless
What colour does phenolphthalein turn in an alkali?
Pink
What colour does Methyl Orange turn in an acid?
Yellow
What colour does Methyl Orange turn in an alkali?
Red
What is an uncertainty?
It’s the degree of error your measurements have with a piece of equipment
-> half the smallest increment the equipment can measure +/-
How do you calculate total uncertainty if you’re using more than one measurement of the same units?
Add the uncertainties.
E.g. 10/2 =5
1/2 =0.5
5+0.5=5.5
How do you calculate percentage error?
Percentage error = uncertainty / reading x 100
What are systematic errors?
Errors caused every time your repeat your experiment
What are random errors?
Errors caused through estimating readings on equipment. They vary with each repeat
What are the benefits of high atom economy?
- less waste, which benefits the environment
- raw materials are used more efficiently, therefore more sustainability
- less by-products, so less time and energy used separating
What compounds are generally soluble in water?
- all group 1 compounds
- all nitrate compounds
- all ammonium compounds
What compounds are generally insoluble in water?
- Ag+ and Pb+ chlorides
- Ba+2 and Pb+2 sulphates
- most hydroxides
- most carbonates