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Unit 1 - Higher Chemistry, Oxidizing and Reducing Agents Questions and Answers oxidation loss of electrons reduction gain of electrons Good reducing agents are? metals elements are good reducing agents as they have a low electronegativity which means they will lose their outer electrons easily Good oxidising agents are? non-metal elements are good oxidising agents as they have a high electronegativity which means they will gain electrons more easily What is a r...

CC7 Questions and Answers Do simple molecular substances conduct electricity? no, there's no charged particles Why do giant covalent bonds have such high melting point? strong covalent bonds that contain a lot of energy to break How do metals conduct electricity and heat? the positive ions are fixed in a sea on delocalised electrons, which are free to move and carry charge. are metals are insoluble in water yes two giant covalent bonds formed from carbon gr...

aqa a-level chemistry amines Questions and Answers What are the four structures of amines? 1. Primary (1°): RNH2 2. Secondary (2°): R2NH 3. Tertiary (3°): R3N 4. Quaternary (4°): R4N+X-. Why is ETHANOL's (alcohol) boiling point higher than ETHYLAMINE's (amide) despite the similar size and Mr? Both have hydrogen bonding BUT the H bonding in ethanol is STRONGER than in ethylamine as the O-H bond is more POLAR than the N-H bond and has potential for more extensive H bonding. ...

AQA A-LEVEL CHEMISTRY Group 2 Questions and Answers GROUP 2 What are the group 2 elements? Magnesium Calcium Strontium Barium Radium [[NOT BERYLLIUM]]. PROPERTIES What is the general trend about electrons? There are two electrons in the outer s-orbital which goes further. PROPERTIES What are the size of the atoms in group 2? The atoms get bigger down the group. Each element has an extra filled main level of electrons compared with the one above it. ...

As-Level Chemistry Paper 1 Questions and answers First Ionisation Energy down Group 2 Alkali Metals First ionisation energy down Group 2 Alkali Metals goes as follows: 1) The ionisation energy decreases as you go down the group 2) This is due to their being extra shielding for the outermost electrons the further down the group you go as well as the further distance between the outer electrons 3) These two occurrences out weigh the power of the increasing positively charged nucleus as you go...

Chemistry A-Level OxfordAQA Definitions Questions and Answers First ionisation energy The energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions Relative atomic/molecular mass The mean mass of an atom/compound of an element, divided by 1/12th of the mass of an atom of carbon-12 Empirical formula The simplest whole number ratio of atoms of each element in a compound Molecular formula The actual number of ato...

AQA A LEVEL CHEM PRACTICALS - PAPER 3 Questions and Answers measuring e.m.f. of electrochemical cells The standard cell potential is the e.m.f. between two half cells making up the cell, measured under standard conditions. clean piece of each metal, e.g. copper and zinc. degrease using propanone, place copper in a beaker with around 50cm₃ 1moldm⁻³ copper sulfate solution, place zinc in a seperate beaker of same concentration and volume zinc sulfate solution join the two beakers with fi...

OCR A level Chemistry Questions and Answers Electronegativity The tendancy of an atom to attract the bonding pair of electrons in a covalent bond Radical A molecule, atom or ion with an unpaired electron Acid (bronsted lowry theory) A molecule or atom that can donate a proton Base A molecule or atom which can act as a proton acceptor Alkali A water soluble base Standard Conditions 298 K, 100 kPa, 1 moldm^-3 Standard enthalpy change of a reaction (...

AQA A-Level Chemistry - Practical’s Questions and Answers (1) Why do we use a white tile? To see indicator colour change better. (1) Why is a conical flask used? Can be swirled without losing any solution. (1) Why is swirling necessary? To ensure that solutions mix and so react completely. (1) Why does rinsing the flask with water not affect the end point? Water does not react ---> doesn't affect number of moles present. (Other 1) Outline how to carry out...

A level chemistry paper 2 Questions and Answers Silver nitrate+ nitric acid + chloride ions White precipitate Silver nitrate+ nitric acid + bromide ions Cream precipitate Silver nitrate+ nitric acid + iodide ions Yellow precipitate Substances that decolorise bromine water Alkenes Electrophiles Electron pair acceptors, attracted to electrons e.g H+ NaF and NaCl Produces misty fumes with conc sulphuric acid NaBr Produces misty and orange/brown fume...

Chemistry 9701 A-Level Questions and Answers Natures of amino acids polar, non-polar, electrically-charged Properties of amino acids white crystalline solids, high melting point, soluble in H2O Effect of pH on enzyme activity increases then decreases above the optimum pH Why does the enzyme activity decrease above optimum pH? the active site is changed due to the ionic bonds Describe the effect of substrate concentration on enzyme activity increases then const...

A-Level Chemistry Atomic structures and isotopes Questions and Answers State what is meant by the term isotopes? Atoms of the same element with different numbers of neutrons. Isotopes of specific element (carbon) have the same chemical properties. Explain why. Same number of electrons in the outer shell. What is the difference between the atomic structures of any given isotopes? You just talk about the number of neutrons present on the isotope. 2) For example, one isotope has...

Excel A level chemistry paper 1 topics Questions and Answers Atoms Made up of 3 subatomic particles - electrons, neutrons and protons Electrons - Subatomic particle - Charge of -1 - Arranged in orbitals - Relative mass of 0.0005 - negligible Nucleus - Where most of the mass of the atom is contained - Made up of protons and neutrons - Diameter is much smaller than that of whole atom Neutrons - Subatomic particle - No charge - Relative mass of 1 - Contained in nuc...

A-Level Chemistry Ion Charges Questions and Answers hyrdogren H+ sodium Na+ silver Ag+ potassium K+ lithium Li+ ammonium NH4+ barium Ba+2 calcium Ca+2 copper(II) Cu+2 magnesium Mg+2 zinc Zn+2 lead Pb+2 iron(II) Fe+2 iron(III) Fe+3 aluminium Al+3 chloride Cl- bromide Br- fluoride F- iodide I- hydroxide OH- nitrate NO3- oxide O-2 ...

AQA A-Level Chemistry - Group 2 Questions and Answers Explain the trend in atomic radius down group 2 Increases down group. Explain the trend in 1st ionisation energy down group 2 -Decreases down group. -More shielding, weaker attraction as nucleus and outer e- further apart. - Easier to remove outer e- (less energy). Explain the trend in melting points down group 2 -Generally decrease down group (not Mg). -Larger ions, distance between + metal nuclei and delocalised e- is g...

OCR A-level Chemistry Reaction Conditions and Reagents Questions and Answers Haloalkane > Nitrile NaCN or KCN (CN-) and ethanol Alkane > Haloalkane Halogen and UV light Haloalkane > Amide NH3 and ethanol Nitrile > Amine H2 and Ni catalyst Haloalkane > Alcohol NaOH Alcohol > Haloalkane Sodium halide and H2SO4 Alkene > Alcohol H2O as steam and H3PO4 Alcohol > Alkene Conc. H2SO4 or H3PO4 and heat Secondary Alco...

AQA A-Level Chemistry Amount of Substance Questions and Answers What is the relative atomic mass? the ratio of the average mass of one atom of an element to one twelfth of the mass of an atom of carbon-12 (Oxford Languages). How do you work out the relative atomic mass? Why is carbon-12 so significant? Carbon-12's atomic mass could be measured particularly accurately compared to the other elements on the periodic table. Historically, chemists and physicists used oxygen to ...

OCR A-level Chemistry - Paper 3 Questions and Answers Why does HF have a higher boiling point than CH4? -Boiling point increases as electronegativity increases -HF has hydrogen bonding, CH4 has London forces How do you prepare a standard solution? -Weigh out correct mass of solid -Dissolve in distilled water -Transfer to a 250cm^3 volumetric flask -Wash beaker with distilled water -Add washings to the volumetric flask -Make up to 250cm^3 with distilled water -Invert to ensure mi...

Transition metals OCR A Level Chemistry Questions and Answers Which 2 transition metals do not have a fully filled 4s orbital? Chromium and copper What advantage does a fully or half filled shell give a transition metal and why? Makes more stable What is the definition of a transition element? D-block element which form at least one ion with a partially filled d orbital Which 2 elements in the d block do not qualify as transition metals and why? Zinc and scandium. Their...

Common exam questions A level chemistry unit 3 Questions and Answers What is meant by an unsaturated hydrocarbon? one which contains one or more carbon-carbon double bonds What is meant by the term hydrocarbon? a molecule that contains the elements hydrogen and carbon only Recall the reagents and conditions needed to produce ethanol from bromoethane. aqueous NaOH reflux Name the organic product and mechanism when 2-bromopropane reacts with ethanolic KOH. prop-1-ene el...