Karteikarten
Qualitive Chemistry
Karten in diesem Stapel (44)
- 1Define ElementA pure substance, which only contains one type of atom
- 2Define AtomSmallest particle of an element. Consists of protons, neutrons and electrons
- 3Define MoleculeTwo or more atoms joined by covalent bonds (share electrons)
- 4Define compoundTwo or more elements ironically bonded (metal/ non metal)
- 5Define substanceGeneral term used for a compound/molecule/atom/element
- 6Define IonA +ve or -ve charged atom or species (e.g. molecules)
cations = +ve
anions = -ve - 7Define symbolshort hand notation for elements
- 8Define formulaThe symbols and number of each type of atom in a compound/ molecule
- 9Define ChargeThe size of any type of +ve or -ve charge;
+1, +2, +3, -1 - 10Define stoichiometryThe molar relationship between reaction quantities
- 11Ions What tells the size of the ion? What are simple ions? What are complex ions? What do metals give? What indicates different charges?There are -ve and +ve ions
The group tell the size of the ion
Ions containing only one element are simple ions
Ions containing more than one element are complex ions
Metals give +ve charges
Roman numerals indicate the charge on elements with more than one charge - 12Stages to construct formulae1. Write out all ions and charges
(Mg 2+, Cl-)
2. Balance the charges
(MgCl2)
3. Put any complex ions in brackets - 133 Examples of common acidsHydrochloric Acid - HCl (aq)
Sulphuric Acid - H2SO4 (aq)
Nitric Acid - HNO3 (aq) - 146 Examples of common gasesAmmonia - NH3 (g)
Carbon Dioxide - CO2 (g)
Carbon Monoxide - CO (g)
Sulphur Dioxide - SO2 (g)
Methane - CH4 (g)
Nitrogen Dioxide (g) - 15What are the diatomic elements?All of group 7
- 16How to balance equations1. Write the word equation
2. Write the correct formula for each species, including the state symbol if necessary
3. Balance the number of atoms on the left and right
4. Check the equation balances and write state symbols - 17Name the 3 different chemical formulas a compound can be described by1. Empirical Formula
2. Molecular Formula
3. Structural Formula - 18Define Empirical FormulaThe simplest whole number ratio of atoms in a molecule
- 19How is the empirical formula obtained?1. Knowing the mass of each element in the compound
Draw a table with the different elements on top and moles on the side. The ratio is then made by dividing by the smallest number of moles
2. From the percentage composition by mass of the compound
Draw a table with the elements on top and the moles on the side (%by mass/ Ar) then divide by the smallest to obtain the ratio - 20Define molecular formulaFormula that shows the actual number of atoms of each element in a molecule
- 21How is the molecular formula found?Molecular formula can be calculated if the molecular mass of a compound is known and you have the empirical formula
n = Mr/ mass of empirical formula
Molecular formula = n(empirical formula) - 22What does the structural formula show?Structural formula shows the arrangement of atoms and bonds within a molecule and is particularly useful in organic chemistry
- 23Define relative atomic massIs the weighted mean of masses of all isotopes of an element relative to one atom of C12
(RAM or Ar)
Atoms mass is measured in a.m.u (atomic mass units) and are relative to carbon -12 taken exactly as 12
mass of one atom of an element/ 1/12 mass of one atom of C-12 - 24Define relative molecular massIs the weighted mean of mass of a molecule relative to one atom of 12C
(RMM or Mr)
mass of one molecule/ 1/12 mass of one atom of 12-C - 25What is the mole and the relationship between the mole, mass and relative molecular massOne mole of compound is its relative molecular or formula mass in grams
Mass of one mole of substance is called its molar mass (Mr) units gmol-1
Moles = Mass/ Mr - 26What is Avogadro's constant?The number of molecules
moles x 6.02 x 10 to the 23 - 27How to calculate the percentage of elements by mass(Mass of the element/ Mr of the compound) x100
- 28What are the properties of chemical reactions?In all chemical reactions;
1. New substances are formed
2. Bonds in the reactants are broken and the products are formed- resulting in an energy change in the system and surroundings
3. A fixed relationship between the number of particles of reactants and products resulting in no overall change in mass - 29What are key features of a chemical equation?1. Reactants are on the left
2. Products are on the right
3. The number of moles must balance - 30What are the state symbols?(s) - Solid
(l) - Liquid
(g) - Gas
(aq) -In Aqueous Solution - 31What do arrows in chemical equations symbolise?A single arrow is used for complete reactions
A double, reversible arrow is used when products and reactants are in equilibrium in the mixture - 32What do co-efficients refer to?The coefficient is the number in front of each reactant and product and it gives information on the molar ratio
- 33Uses of ionic equationsBecause ionic compounds are completely dissociated in solution, it is sometimes better to use ionic equations and include the charge
- 34How to measure the molar quantities for solids, liquids, gases and solutionsMass for SOLIDS: Weighed - 1kg = 1000g
Mass for LIQUIDS: Density = mass/volume (gcm-3)
Mass for GASES: Mass or volume can be used
Mass for SOLUTIONS: Volume is normally used, and the concentration is the amount of solute in a known volume of solution - gdm-3/moldm-3 - 35What is the relationship between moles and gases?1 mole of any gas at standard temperature and pressure occupies a volume 22.4dm3
(1000 cm3 = 1 dm3)
Moles = gas volume/ 22.4
Gas volume = moles x 22.4 - 36Describe solvent, solute, solution and concentrationSOLVENT - The dissolving medium (usually water)
SOLUTE - The dissolved substance
SOLUTION - The solvent and solute mixed together
CONCENTRATION - The amount of solute per volume of solution - 37What is the relationship between moles and solutions?The more of the solute dissolved in the solution, the more concentrated it is
The more of the solvent added, the less concentrated it is (dilute)
Concentration = moles/ volume
(Conc, moles, vol) - 38Describe neutralisation ReactionsA neutralisation reaction occurs when acids and bases react:
1. ACID + BASE --> Salt + Water
2. ACID + METAL CARBONATE --> Salt + Water + CO2
3. ACID + METAL --> Salt + Hydrogen gas
NB. If the base is NH3, only a salt is produced - 39What do titrations involve?Titrations involve 2 solutions -
1. A standard solution (The known concentration)
2. A solution of unknown concentration - 40How to determine the concentration of an unknown solution1. Write the balanced equation for reaction
2. Write the ratio
3. Calculate the number of moles in the standard solution (moles = concentration x volume (in dm3))
4. Use the balanced equation to calculate the number of moles in solution B, which must have reacted
5. Use volume and moles to calculate the concentration of the unknown solution
(Concentration = moles/ volume (dm3)) - 41How to calculate percentage purity by massmass of the pure compound/
total initial mass
x100 - 42What is ideal gas?PV= nRT
Where;
P= Pressure (pa)
V= Volume (m3)
n= Number of moles
R= The gas constant (8.314 JK-1 mol-1)
T= Absolute temperature (K) - 43What are real gases?Real gases obey all the laws of gas. Most gases behave like ideal gases at high temperature and low pressure
Units are in JK-1mol-1 - 44What are the 3 variables for gases (in fixed amounts)?VOLUME: At constant volume, increasing the temperature increases the kinetic energy and therefore the force the particles collide. Pressure increases directly proportionally to absolute temperature
TEMPERATURE: At constant temperature, as the volume decreases, kinetic energy of the particles increases, resulting in more collision. The increase in pressure is inversely proportional to the volume (Doubling the pressure halves the volume)
PRESSURE: At constant pressure, if temperature is increased, the particles will have greater average velocity, so will collide more. To stop this, volume must increase. Increase in volume is directly proportional to absolute temperature (doubling temperature doubles the volume)
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- IB Chemistry Karteikarten am Qualitive Chemistry, erstellt von P H am 04/02/2015.
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