AS Level Chemistry Complete Guide Question And Answers.

Atomic number - correct answer Number of protons in an element Mass number - correct answer Number of protons and neutrons Ion - correct answer Electrically charged particle formed by the loss/gain of electrons Relative masses of P,N and E - correct answer 1,1, 1/2000 (respectively) Isotopes - correct answer Atoms of the same element with different number of neutrons but same number of protons. What are steps of mass spectroscopy? - correct answer Ionisation, Acceleration, Deflection, Detecting Ionisation - correct answer A gaseous sample is bombarded with high energy electrons to create 1+ ions Acceleration - correct answer They are accelerated through magnetic/electric field Deflection - correct answer Ions are deflected through magnetic field according to mass (heavy - deflect least)(light - deflect most) Detection - correct answer A calibrated detector records degree of deflection and interprets this into mass What does mass spectroscopy provide? - correct answer Information about masses of particles inside machine and how often it's detected. What is shown on mass spectrum? - correct answer Different isotopes relative abundance and molecular peak is furthest to right Molecular ion peak - correct answer Peak corresponding to relative molecular mass of the compound (parent peak) Why are there sometimes line after the parent peak? - correct answer They are a result of carbon 13 isotope and isn't considered when identifying a compound 1st Ionisation energy - correct answer The energy change when 1 mole of electrons is removed from 1 mole of gaseous atoms to form 1 mole of gaseous 1+ions Nth Ionisation energy - correct answer Energy required to remove 1 electron feom each (n-1)+ ion in 1 mole of gaseous (n-1)+ ions to form 1 mole of gaseous n+ions Ground state - correct answer Natural state of existence with electrons in lowest energy position Orbital - correct answer Region around atom nucleus which can hold maximum of 2 electrons What's responsible for trends of 1st IE in first 20 elements? - correct answer Sub-shells Describe an S-orbital - correct answer Simplest of all, is spherical. The quantum number dictates how far away from the nucleus it is. Describe P-orbital - correct answer Elongated dumbbell shape vary in charge density with area of greatest concerned increasing with distance from nucleaus due to principle quantum number. Have 3 different orientation of spaces. (x,y,z) Electron configuration points to consider - correct answer S-orbital have less energy than d orbitals of principle quantum numbers. Always fill orbital with 1 electron first before pairing. Electrons have different directions of spin. Why do you fill each orbital with one electron before adding in pairs? - correct answer Two electrons in same orbital experience some repulsion making pairing less favourable Valency - correct answer Number of electrons involved in characteristic properties of element (reactions) What are the main ionic compounds to know? - correct answer SO4(2-), NO3(-),NH4 (+), CO3 (2-), OH (-), Zn (+), Ag (+) Halide ion test with NaCl (Ionic equation) - correct answer Ag (+)(aq) + Cl (-)(aq) AgCl (s) Relative atomic mass - correct answer The weighted mean mass of an atom of an element compared to 1/12 of the mass of carbon 12. Relative Isotopic mass - correct answer The mass of an isotope of an element compared to 1/12 of the mass of carbon 12 Relative molecular mass - correct answer The weighted mean mass of a molecule compared to 1/12 of the mass of carbon 12. Relative formula mass - correct answer The weighted mean mass of a formula unit compared to the mass of 1/12 of the mass of carbon 12. 1 mole - correct answer The amount of substance that contains as many elementary particles as there are in 12 of carbon 12. Avogadro's constant (Number of particles per mole) - correct answer 6.02e^23 Molar mass - correct answer The mass of one mole of a substance. (g mol-1) Relationship between mass, Molar Mass and Moles - correct answer M=m/n Empirical formula - correct answer The simplest whole number ratio. Molecular mass - correct answer The number and different type of atoms of each element in a molecule. Water of crystallisation - correct answer Salts with water present in crystal form Anhydrous - correct answer A compound with no waters of crystallisation. Hydrated - correct answer A compound with water in its structure. Avogadro's law - correct answer Equal volumes of gases measured at the same temperature and pressure will contain the same number of molecules. What are standard conditions? - correct answer 0°C (273°K) and 100kPa. Molar volume= 22.1dm3 What are conditions at RTP? - correct answer 25°C (298°K) and 100kPa Molar volume= 24dm3 Relationship between moles of gas and gas volume - correct answer n (mol)=V(cm3/dm3)/molar volume (cm3/dm3) Ideal gas equation - correct answer PV=nRT Conditions in ideal gas equation - correct answer T=°K V=dm3=P=kPa V=cm3=P=Pa Relationship between Temp, pressure and volume - correct answer P1V1/T1 = P2V2/T2 Relationship between concentration, moles and volume - correct answer n (moles)=Conc(mol dm-3)×Vol(dm-3) What are cations? - correct answer Positive ions What are anions? - correct answer Negative ions What's a precipitate - correct answer A solid formed when two liquids react Oxidation - correct answer Loss of electrons Reduced - correct answer Gain of electrons Rules of Oxidation numbers - correct answer Natural elements=0 Oxi no total 0 Oxi no of ion totals ionic charge. Priorities of Oxidation states - correct answer Groups 1,2&3 have Oxi no of +1,+2&+3 respectively. Flourine=-1 Hydrogen~+1 Oxygen ~-2 Chlorine~-1 Oxidising agent - correct answer Is reduced in itself (gains electrons easily) {Flourine} Reducing agent - correct answer Is oxidised itself (loses electrons readily) {Ba} Acid - correct answer Proton donor