7315555
Description
Flashcards by Kayla Price, updated more than 1 year ago
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Created by Kayla Price
over 7 years ago
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| Question | Answer |
| What happens to the ionisation energy of the elements going down group 2? | IE decreases as number of shells increases, increasing shielding and increasing the distance between the outer electrons and the nucleus. This reduces the electrostatic attraction between the nucleus and outer electrons. This means less energy is required to remove electrons. |
| How does reactivity change going down group 2? | Going down the group, ionisation energy decreases, so the outer electrons are more likely to be removed. This means reactivity increases. |
| What is produced in a reaction between a group 2 metal and water? What doesn't react? | A metal hydroxide and hydrogen. Be does not react. |
| What is produced when a group 2 metal is burned in oxygen? | Solid white oxide |
| What is produced when a group 2 metal is reacted with chlorine? | A solid white chloride |
| Are group 2 metal oxides and hydroxides acids or bases? Why? | Bases because they produces OH- ions (proton accepting) |
| Which group 2 metal oxide does not react with water? | Beryllium oxide |
| How does the pH of group 2 metal hydroxide solutions change as you go down the group? | pH increases as hydroxides become more soluble, increasing the amount of OH- ions. |
| How does solubility of group 2 metal hydroxides change going down the group? | Increases because OH- has a single charge. |
| How does solubility of group 2 metal sulfates change going down the group? | Decreases because sulfate ion has a 2- charge |
| Explain how the thermal stability of carbonates and nitrates changes going down a group | Thermal stability increases going down the groups as the ionic radius of the metal ions (cations) increases. The larger radius causes the electron density to decrease so the polarising power of the cation decreases. The larger the polarising power of the cation the more it can distort the anion, weakening the bond. This means less energy is required to overcome the electrostatic attraction between the two and so the compound becomes less stable. Group 1 compounds are more thermally stable than group 2 compounds as the cation only has a 1+ charge rather than a 2+ charge, so its polarising power is lower. |
| What is produced when a carbonate decomposes? | The metal oxide and carbon dioxide |
| Which of the group 1 carbonates can decompose? | Lithium carbonate |
| What is produced when a group 1 nitrate thermally decomposes? | A nitrite and oxygen, except for lithium nitrate which forms lithium oxide, nitrogen dioxide and oxygen |
| What is produced when group 2 nitrates thermally decompose? | The oxide, nitrogen dioxide and oxygen |
| How would you test for the thermal stability of nitrates? | Finding how long it takes to produce a sufficient amount of oxygen to relight a glowing splint. Finding how long it takes until a certain amount of brown NO2 gas is produced. |
| How would you test the thermal stability of a carbonate? | How long it takes for the CO2 produced to turn lime water cloudy. |
| What is the flame colour for lithium? | Red |
| What is the flame colour for sodium? | Orange/yellow |
| What is the flame colour for potassium? | Lilac |
| What is the flame colour for rubidium? | Red |
| What is the flame colour for caesium? | Blue |
| What is the flame colour for calcium? | Brick red |
| What is the flame colour for strontium? | Crimson |
| What is the flame colour for barium? | Green |
| How would you carry out a flame test? | 1) Dissolve the compound in hydrochloric acid 2) Heat nichrome wire on a bunsen flame to clean it 3) Dip the wire into the mixture and put it in the flame, note the colour. |
| What is an electron transition? | The movement of electrons between energy levels |
| Why do different compounds have different flame colours? | The energy absorbed from the flame causes electrons to move to higher energy levels. As the electrons fall back down to their original energy levels they release energy in the form of light - producing a significant colour. The colour is determined by the difference in energy between higher and lower energy levels producing different wavelengths of light. |
| How does electronegativity change going down group 7? | It decreases as shielding increases, increasing the distance between the nucleus and the bonding electrons. This decreases the nucleus' ability to attract the electrons. |
| Why do the halogens have low solubility in water? | They're non-polar |
| What is the colour of chlorine in water and in hexane? | virtually colourless |
| What is the colour of bromine in water and in hexane? | Yellow/orange and orange/red |
| What is the colour of iodine in water and in hexane? | Brown and pink/violet |
| What happens to the reactivity of the halogens as you go down the group? | They become less reactive as you go down because they get larger so outer electrons are further from the nucleus. This makes attracting an electron to form an ion harder. |
| How does the melting point of the halogens change as you go down the group? | It increases as number of electrons increases, increasing strength of london forces. |
| What occurs when a halogen is mixed with a halide? | The halogen will displace the halide ions from solution, forming a new halide solution and the displaced halogen |
| How is a displacement reaction between halogens and halides a redox reaction? | The thing displaced is oxidised: 2Br- --> Br2 + 2e- The thing that displaces is reduced: Cl2 + 2e- --> 2Cl- |
| What colour change is observed when bromine is displaced from a halide solution, forming Br2? | Colourless --> Orange |
| What colour change is observed when iodine is displaced from a halide solution, forming I2? | Colourless --> Brown |
| How would you make it easier to distinguish whether iodine or bromine is displaced from a halide solution? | Add and organic solvent - the halogen will dissovle in the solvent and form a layer above the aqueous solution. This makes the bromine more orange and iodine more of a pink/violet. |
| What is a disproportionation reaction? | When a species is simultaneously oxidised and reduced. |
| What is produced when a halogen reacts with cold dilute alkali (NaOH)? What is the name of the reaction? | OX- (chlorate(I), bromate(I), iodate(I) ions), halide ions and water Disproportionation reaction |
| What is the name and oxidation state of the halide of the following ions: 1) Cl- 2) Cl 3) ClO- 4) BrO- 5) BrO2 - 6) IO3 - 7) IO4 - | 1) Chloride, -1 2) Chlorine, 0 3) Chlorate(I), +1 4) Bromate(I), +1 5) Bromate(III), +3 6) Iodate(V), +5 7) Iodate(VII), +7 |
| What is produced when hot alkali is added to a halogen? | Chlorate(V)/Bromate(V)/Iodate(V), halide ions and water |
| How does the reducing power of the halides change as you go down the group? | It increases as outer electrons become easier to remove due to the increase in the distance and therefore attraction between the electrons and the nucleus. |
| Describe the difference between the reaction of KF/KCl with sulfuric acid and the reaction of KBr with sulfuric acid | The first reaction forms a hydrogen halide, the F-/Cl- ions are not strong enough reducing agents to reduce the sulfuric acid so the reaction stops. The second reaction forms the hydrogen halide, but because Br- ions are stronger reducing agents a second reaction occurs. They react with the sulfuric acid in a redox reaction, producing sulfur dioxide, water and orange fumes of Br2. |
| Describe the difference between reaction of KBr with sulfuric acid and KI with sulfuric acid | In the KBr reaction the hydrogen halide produced goes on to reduce the sulfuric in a second reaction to form sulfur dioxide and Br2 gas. In the KI reaction the same second reaction occurs, producing SO2. The HI then goes on to reduce the SO2 further in a third reaction, forming H2S and I2. |
| What is produced when hydrogen halides react with ammonia? | Smoky white fumes of NH4X(s) eg. NH4Cl(s) |
| How would you test for the halides? | Add dilute nitric acid to the halogen to remove ions which might interfere with the reaction. Then add siver nitrate solution (AgNO3). This forms a silver halide precipitate. The colour of this precipitate identifies the halide present: F- = no precipitate (AgF soluble) Cl- = white Br- = cream I- = yellow To make them more distinguishable, ammonia solution is added. AgCl dissolves when dilute ammonia is added, AgBr dissolves when conc. ammonia is added and AgI does not dissolve. |
| How would you test for carbonate (CO3 2-) / hydrogencarbonate (HCO3-) ions? | Reacting with hydrochloric acid produces CO2, which can be tested for by bubbling it through lime water. |
| How would you test for sulfate ions (SO4 2-)? | Add dilute HCl and barium chloride. The test is positive if a white precipitate of barium sulfate forms. |
| How would you test for ammonia gas? | Use damp red litmus paper, the ammonia dissolves in the water on the paper and turns it blue. |
| How would you test for whether a substance contains ammonium ions? | Add sodium hydroxide and heat gently. Hold damp litmus paper above the mixture to see if any ammonia gas is given off, which will turn the paper blue. |
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