AQA AS Chemistry Unit 1 Foundation Chemistry – Flashcards
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| Define electronegativity. |
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| The power of an atom to withdraw electron density from a covalent bond |
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| Define the term relative atomic mass of an element. (1) |
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| average mass of one atom of an element x12 mass of one atom of carbon-12 |
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| Describe and explain the trend in boiling and melting points going across period 3. |
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| Across the metals (Na, Mg, Al) MP and BP increase as the number of delocalised electrons increases, making metallic bonding stronger. Si has a high MP and BP due to its giant covalent structure. In the non-metals with simple molecular structures, MP and BP are dependent on the size of the molecule: the greater the molecular surface area, the stronger the van der Waals forces between molecules, so the higher the MP and BP. |
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| Explain how NO is produced in the engine of a motor vehicle. (2) |
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| Nitrogen and oxygen in the air react (1) at high temperatures/with a spark (1). |
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| Explain why the value of the first ionisation energy of sulfur is less than the value of the first ionisation energy of phosphorus. |
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| Paired electrons in the 3p subshell of sulfur repel. In phosphorus there are no paired electrons in the 3p subshell. |
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| For a metal, is the atomic or ionic radius bigger and why? |
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| Atomic; outer shell is emptied when an ion is formed |
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| For a nonmetal, is the atomic or ionic radius bigger and why? |
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| Ionic; extra repulsion causes the charge cloud to expand |
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| How many structural isomers does butane have? |
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| 2 |
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| How many structural isomers does pentane have? |
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| 3 |
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| How many structural isomers does hexane have? |
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| 5 |
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| List four pollutants produced by burning fuels. |
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| Sulfur dioxide, carbon monoxide, particulates and nitrous oxides. |
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| Name the homologous series with the functional group -OH. |
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| Alcohols |
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| Name the homologous series with the functional group C=C. |
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| Alkenes |
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| Name the homologous series with the functional group R-CO-R. |
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| Ketones |
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| Name the homologous series with the functional group R-COH. |
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| Aldehydes |
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| Name the homologous series with the functional group R-COOH. |
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| Carboxylic acids |
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| Give two problems associated with the emission of sulfur oxides. |
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| Acid rain; causes problems for people with asthma. |
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| State a use of ethene. |
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| Making plastics/used to make polyethene |
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| State the meaning of the term structural isomers. (2) |
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| Compounds which have the same molecular formula (1) but different structural formula (1) |
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| State the shape and bond angle in a molecule of BF3. |
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| Trigonal planar; 120 |
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| State the shape and bond angle in a molecule of CO2. |
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| Linear; 180 |
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| State the shape and bond angle of ClF4-. |
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| Square planar, 90o |
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| State the shape and bond angle of H2O |
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| Non-linear; 104.5 |
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| State the shape and bond angle of NH3. |
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| Trigonal pyramidal/distorted tetrahedral; 107 |
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| State the shape and bond angle of NH4+ |
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| Tetrahedral; 109.5 |
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| State the shape and bond angle of SF6. |
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| Octahedral; 90 |
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| State the shape and bond angles of PCl5. |
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| Trigonal bipyramidal; 120,90 |
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| What are the conditions for catalytic cracking? |
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| 450oC, up to 10atm, zeolite catalyst |
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| What are the conditions for thermal cracking? |
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| Up to 900oC, 70atm |
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| What are the five steps of mass spectrometry? |
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| Vaporisation, ionisation, acceleration, deflection, detection |
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| What are the main products of catalytic cracking? |
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| Motor fuels and aromatic hydrocarbons |
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| What environmental problems result from nitrous oxide pollutants? |
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| Acid rain and photochemical smog |
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| What happens to atomic radius across a period and why? |
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| It decreases due to increased nuclear charge. |
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| What happens to electronegativity across a period and why? |
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| Increases; greater nuclear charge to attract electrons |
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| What is a free radical? |
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| An atom or molecule with an unpaired electron |
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| What is a functional group isomer of an alkene? |
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| A cycloalkane. |
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| What is the charge on a barium ion? |
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| 2+ |
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| What is the charge on a calcium ion? |
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| 2+ |
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| What is the charge on a carbonate ion? |
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| 2- |
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| What is the charge on a hydrogen ion? |
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| 1+ |
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| What is the charge on a hydroxide ion? |
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| 1- |
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| What is the charge on a lead ion? |
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| 2+ |
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| What is the charge on a lithium ion? |
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| 1+ |
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| What is the charge on a magnesium ion? |
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| 2+ |
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| What is the charge on a nitrate ion? |
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| 1- |
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| What is the charge on a potassium ion? |
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| 1+ |
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| What is the charge on a silver ion? |
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| 1+ |
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| What is the charge on a sodium ion? |
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| 1+ |
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| What is the charge on a sulphate ion? |
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| 2- |
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| What is the charge on a sulphide ion? |
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| 2- |
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| What is the charge on a zinc ion? |
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| 2+ |
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| What is the charge on an aluminium ion? |
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| 3+ |
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| What is the charge on an ammonium ion? |
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| 1+ |
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| What is the charge on an oxide ion? |
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| 2- |
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| What is the economic reason for the cracking of crude oil? |
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| To produce substances which are in greater demand. |
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| The electron configuration of Vanadium (V) is (1s^2)(2s^2)(2p^6)(3s^2)(3p^6)(3d^3)(4s^2).What is the electron configuration of a V3+ ion? |
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| (1s^2)(2s^2)(2p^6)(3s^2)(3p^6)(3d^2) |
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| What does it mean for two species to be isoelectronic? |
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| They have the same electron configurations |
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| What is the electron configuration of chromium and why does it defy the trend? |
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| 1s^2.2s^2.2p^6.3s^2.3p^6.3d^5.4s^1; the 4s subshell promotes an electron to the 3d to become more stable. |
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| What is the electron configuration of copper and why does it defy the trend? |
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| 1s^2.2s^2.2p^6.3s^2.3p^6.3d^10.4s^1; the 4s subshell promotes an electron to the 3d subshell to become more stable. |
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| What is the ideal gas equation? |
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| pV=nRT |
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| What is the main advantage of catalytic cracking over thermal cracking? |
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| Lower temperature and pressure - lower cost. |
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| What is the trend in ionisation energy going down a group? (3) |
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| Ionisation energy decreases. (1) The atomic radius increases (1) and there is more electron shielding as you go down the group (1) |
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| What is used to remove sulphur dioxide emissions and why? |
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| Calcium oxide; it is basic so it neutralises the gas. |
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| What metal is used as a catalyst in a catalytic converter? |
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| Platinum |
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| What three factors affect ionisation energy? |
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| Nuclear charge, atomic radius and shielding |
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| What type of catalyst is used in catalytic cracking? |
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| Zeolite |
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| What type of cracking produces lots of alkenes? |
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| Thermal cracking |
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| What type of crystal structure does graphite have? |
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| Giant covalent/macromolecular |
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| What type of mechanism is catalytic cracking? |
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| Carbocation mechanism |
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| What type of reaction is thermal cracking? |
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| A free radical reaction. |
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| When forming positive ions, which empties first - the 3d subshell or the 4s subshell? |
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| 4s |
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| Why do the boiling points of nonmetals increase down a group? |
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| Larger molecules = stronger van der Waal's forces |
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| Why does an alkene have a similar boiling point to its alkane equivalent with the same number of carbon atoms? (2) |
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| Similar molecular surface area (1), so similar van der Waal's forces between molecules (1) |
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| Why does ionisation energy drop slightly between groups 2 and 3? |
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| The p subshell is further from the nucleus than the s subshell |
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| Why does ionisation energy drop slightly between groups 5 and 6? |
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| Paired electrons in the p subshell repel |
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| Why does ionisation energy increase across a period? |
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| Decreased atomic radius and increased nuclear charge. |
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| Why does thermal cracking require large temperatures? |
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| To break C-C and C-H bonds |
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| Why is platinum coated on a ceramic honeycomb in a catalytic converter? |
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| Maximised surface area |
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| Why is the boiling point of iodine low? (2) |
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| Van der Waals forces between molecules (1) are weak (1) |
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| Write an equation to show how NO is removed from the exhaust gases in motor vehicles using a catalytic converter. |
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| 2NO+2CO=>N2+2CO2 |
