amount of substance Flashcards
State Avogardo’s Law
Under the same temperature and pressure, one mole of any gas would occupy the same volume
What are the benefits for sustainability of developing chemical processes with a high atom economy?
- Less waste product produced, therefore less waste product is needed to be disposed of in the environment
- Lower energy demands for reaction conditions are cheaper to run and better for the environment
- Non-renewable sources are better for the environment
How do you rearrange the ideal gas equation to work out temperature
T = PV / nR
What does atom economy tell us?
The proportion of desired products compared with all the products formed in the reaction
What are the ideal ways in which gases behave?
- They are in continuous motion
- No intermolecular forces experienced
- Exert a pressure when they collide with each other or container
- No kinetic energy is lost in the collisions
- When temperature increases, kinetic energy of gases increases
Which type of reaction has 100% atom economy?
Addition reactions
two or more reactants are combined to form a product
Does 100% yield mean 100% atom economy and why?
- No
- Even if all reactants are converted into products, not all products of the reaction will be the desired product
How do you rearrange the ideal gas equation to work out pressure
p = (nRT) / V
How do you calculate the moles of a gas?
moles = volume (dm3) / 24
How much volume does a gas occupy, at room temperature and pressure?
24dm3
What is the equation to calculate solution volume?
volume = moles / concentration
What does the Avogardo constant represent
The number of atoms per mole of the carbon-12 isotope
How do you rearrange the ideal gas equation to work out moles
n = PV / RT
What are the units for the ideal gas equation
Pressure = Pa
Volume = m3
Gas constant = 8.314 J mol-1
Temperature = K
What is the pressure and temperature at r.t.p?
Pressure = 100 kPa / 1atm Temperature = 298 K / 25°C
What is the unit used to measure amount of substance
moles
1 atmospheric pressure (atm) is equal to how many pascal (Pa)?
1 atm = 101,325 Pa
What is the symbol for amount of substance?
n
What are the 4 common state symbols?
(s) = solid (L) = liquid (aq) = aqueous (g) = gaseous
How do you calculate the mass of 1 mole of the element?
mass = mol x mr
0°C is equal to how much kelvin (K)?
273 K
What does the concentration of a solution mean?
It is the amount of solute dissolved in 1 dm3 of solvent
How do you rearrange the ideal gas equation to work out volume
V = (nRT) / P
What is a substitution reaction?
A substitution reaction is one where some atoms from one reactant are swapped with atoms from another reactant - it forms at least two products.
What do the terms concentrated and dilute mean?
Concentrated = large amount of solute per dm3 of solvent
Dilute = small amount of solute per dm3 of solvent
What does the percentage yield mean?
The efficiency of which reactants are converted into products
What is a species in a chemical reaction?
Any particle that takes a part in a reaction
What are the reasons for not obtaining 100% yield?
- Reaction may be at equilibrium
- The reactants may be impure
- Side reactions could occur
- Reactants or products may be lost when transferring
- Loss of products during seperation and purification
What is the ideal gas equation
pV = nRT
How is atom economy calculated
(mr of desired product / sum of all the mr of all the products) x 100
Why do different gas particles occupy the same volume?
The gas particles are very spread out, hence individual differences have no effect
How is percentage yield calculated?
(actual amount of product / theoretical amount of product ) x 100
What does a low atom economy mean and why is it not ideal?
- Low atom economy means there are waste products produces
- It costs money to separate the desired product from the waste products and more money to dispose of the products safely
- Less sustainable, many raw materials are in limited supply. Raw materials come from renewable sources and are better for the environment than materials from non-renewable sources.
How do you convert moles into grams?
mass = moles x mr
Define molar gas volume
The volume per mole of gas molecules
How do you calculate moles when concentration and volume are given?
moles = concentration x volume
What is a standard solution?
A solution of known concentration
How do you calculate moles when mass and mr are given?
Moles = mass / mr
What is the equation to calculate solution concentration?
concentration = moles / volume
What is the theoretical yield?
Theoretical yield is the mass of product that should be made in a reaction if no chemicals are lost in the process
Describe the steps taken to prepare a standard solution
- Weigh the solute
- In a beaker dissolve the solute using the solvent
- Pour the solution into a volumetric flask
- Rinse the beaker using the solution and add it to the flask
- Add solvent to the flask carefully until it reaches the graduation line
- Mix the solution thoroughly to ensure complete mixing
How do you convert cm3 into m3
divide by 1 x 10^6
How do you convert dm3 into m3
divide by 1000
How do you convert °C into K
add 273
How do you convert kPa into Pa
multiply by 1 x 10^6
