Chemistry Flashcards

Question

Air Pollution

Answer 1

Pollutants that are as a result of not completely burning harmful gasses **Complete combustion** Hydrocarbon + oxygen ➔ water + carbon dioxide lead to particulates(soot) and carbon monoxide **Particulate** - respititory problems - Smog - Global Dimming **Carbon monoxide** - Diffuses into blood meaning less oxygen is transported around the body - Oxygen deprivation - Colorless and oader less Nitrogen oxides and sulfur dioxides cause acid rain

Answer 2

**Ion** - is a charged particle, can be a single or group amount of atoms Ions are formed by gaining or losing an electron(s) do this to get a complete outer shell Periodic table, group number is the amount of atoms in the outer shell To become stable they must lose or gain electrons Requires energy to change amount of electrons so is easier for the ones who only require 1 or 2 Group 1,2,6,7 all easiest to become an Ion as they only need 1 or 2 group 3,4,5,6 hardest Na -> Na+ + e- e = Electron with a negative charge

Answer 3

**Ions** - Formed when atoms lose or gain electrons Transfer electrons to stabiles both atoms e.g. gain 1 and lose one Two ions have opposite charges so will be attracted as opposites attract Ionic Bond is formed Using a dot and Cross Diagram - Use to know which electrons belong to which atom - Box with square brackets and + or - to show charge

Answer 4

**Metals** normally form ions which have a positive charge **Non metals** usually have a negative charge From in a **Lattice** structure **Properties** - Very high melting and boiling points - can conduct electricity only when melted and dissolved in water - Strong ionic Bonds - Requires a lot of energy to break apart - When solid everything is fixed - when they can move about depends on the charge allows the conductivity of electricity **Formula** Chemical symbol together if one has 2 electrons would be xy2

Answer 5

**Covalent bonding** Bonds when two **Non Metal** elements with the same requirements e.g. need electrons They can **share** electrons so will share 1 each, both get 1 extra Dot and Cross diagram and a space to overlap Cl-Cl Shares what they need so become bonded together

Answer 6

**Simple Molecular Substances** - Small easy formations **Giant Covalent structures** - Forms things like diamonds Covalent bonds are very strong **Simple** Just need to break the intermolecular forces so wont require a lot of energy More intermolecular forces require more energy to break them a part Do not conduct electricity and have no electric charge **Giant** - Huge numbers of non metal atoms - regular repeating lattices - Diamond, graphite and silicon dioxide - very strong - high melting and boiling points - dont conduct electricity

Answer 7

Only made of Carbon Giant Covalent bond **Allotrope** - Different structural forms of the same element in the same physical state Regular lattice, making them very strong **Diamond** - Each carbon atom is covalently bonded to 4 other carbon atoms - recognisable - very strong - doesn't conduct electricity **graphite** - Bonded to only 3 carbon atoms - Arranged into hexogen's to arrange several layers - Each layer held together weakly - relatively soft - high melting point - Layers can slide - One spare electron which becomes **delocalized** - Can conduct electricity and heat due to it - One layer known as graphene

Answer 8

Allotropes of Carbon **Fullerenes and graphene** Each layer of graphite is known as graphene very strong bond. Graphene can conduct electricity Graphene is completely natural Graphene tubes and spheres are known as fullerenes **fullerenes** - act as spheres around other molecules like a cage to get specific dosages to specific areas - Can also be used as an industrial catalyst - Large surface area - Nanotubes for Nano technology - Very long and thin first ever known as **Buckminsterfullerene** - Hallow sphere - 60 carbon atoms C60 - Nanotechnology

Answer 9

Bonding between metal atoms Giant structure of atoms arranged in a regular pattern Share with all the other atoms in the metal All become positive atoms and the delocalized electrons run in between strong electrostatic attraction between delocalized electrons and the positive metal atoms high melting and boiling point good conductor of electricity and heat metals are malleable due to the different layers being able to slide over each other **Alloys** - Contain 2 or more different elements picked with different sized atoms - disrupts the metals regular pattern - the different layers cannot slide over each other as easily Examples: **Steel** made from Iron, carbon and sometimes chromium manganese and vanadium

Answer 10

Mass numbers = the larger number of the symbol Relative atomic mass (Ar) - Average mass of all the isotopes of that element Relative formula mass - Add together the relative atomic masses of all the atoms in that compounds molecular formula. **Example** H2SO4 4 O = 4x16 = 64 2 H = 2x1 = 2 1 S = 1x32 = 32 32+2+64= 98 Mr=98 **Calculate the percentage mass of a particular mass in a compound.** **Example** H2SO4 Percentage mass of S (Ar of S x Number of S) / Mr of the H2SO4 x 100 32 x 1 / 98 =0.327 0.327 x 100 = 32.7%

Answer 11

**Formula** Number of moles in a sample = Mass of that element / Mr **Mole** - Unit to measure the amount of a chemical we have 1 Mole of any substance that contains 6.02 x 10^23 Known as **Avogadro's constant** Will be the same as relative formula mass in grams equal to the Mole of a substance

Answer 12

Conservation of mass is that mass is always conserved **No atoms are created or destroyed, only the bonds change** Amount of atoms doesn't change based on the equitation If scales used mass should stay the same Mass may appear to change if it dispersed into surroundings **chemical change** - Rearrangements of the atoms in the reactants to form the products

Answer 13

**Limiting reactants** - It all reacts and limits how much product can be formed once all of the reactant has been used up Refers to the reactant that is fully used up known as the **limiting reactant** Whatever other reactant is known as being in **excess** Limiting factor changes the amount of product

Answer 14

Measured in grams per decimeter cubed = 1000cm Concentration = Mass/Volume Mass = G Volume = dm^3

Answer 15

**Ph** Measure of how acidic or alkaline a solution is **Ph Scale** 0- Red Highly acidic 1- Red Highly Acidic 2- Red Highly Acidic 3- Orange/red Strong Acidic 4 - Orange Acidic 5 - Orange/Yellow Less acidic 6 - Yellow Weak Acidic 7 - Green Neutral 8 - Turquoise Weak Alkaline 9 - Blue Less Alkaline 10 - Purple/Blue Alkaline 11 - Purple Strong Alkaline 12 - Purple Highly Alkaline 13 - Purple Highly Alkaline 14 - Violet Highly Alkaline Pure water is 7 (Neutral) pH measured using an indicator, chemical dyes based on pH level. Wide range indicators **Universal Indicator** makes the colour of the normal pH scale **pH probe** - Electronically measure the pH - Much more perceive and there is no room for misinterpretation of the colour **Acid** - Any substance that forms an aqueous solution with a pH less than 7 **Bases** - Any substances with a pH greater than 7 **Alkalis**- A base that dissolves in water to form a substance of pH 8 or higher **Neutralization reaction** Acid and Base combine to form a neutral substance making the pH roughly 7 (Neutral) **Acids** - Hydrochloric acid HCl - sulfuric acid H2SO4 - Nitric Acid HNO3 **Base** - Sodium Hydroxide NaOH - Calcium Carbonate CaCo3

Answer 16

**Acid** - Substance that forms aqueous solutions with a pH less than 7 - Ionize with the aqueous solution **Strong Acid** - All of the acids particles will Disassociate **Example** Hydrochloric acid Hcl Nitric Acid HNO3 Sulfuric acid **Weak Acid** - Dont fully ionize - dissociation of weak acids is reversible reaction - Equilibrium Shift to the **left** **Examples** - Citric acid - Ethanoic Acid - Carbonic Acid **Concentration ** - How much acid there is in a certain volume. **Strength** - How much an acid dissociates **Higher Hydrogen the pH gets lower** each pH is equivalent to a factor of 10

Answer 17

Acid reacting with, Metal oxides or metal hydroxides or metal carbonates all class as a neutralization reaction **Metal Oxides/ Hydroxides** whenever reacted with acid would produce salt and water Metal Oxides/hydroxides + Acid -> Salt + water Take negative from the acid and positive from the base **Metal Carbonates** Produces salt, water and Carbon dioxide Acid + Metal Carbonates -> Salt, H20+ CO2 **Soluble salts** Sodium Chloride NaCl Potassium Sulfate K2SO4 Calcium Nitrate Ca(NO3)2 **Insoluble base** - Place acid dilute in a beaker and gently heat over budson burner - Add insoluble base a little bit at a time - When it stops disappearing the base has become an excess - Acid has been neutralized - Filter any excess Should give solution To get crystals - Water bath at a gentle temp - When first crystals stop heating and more will form - Filter crystals and dab dry leaving in a warm place

Answer 18

**Oxidation** - gaining oxygen **Reduction** - Lose of oxygen **Oil Rig Acronym** **O**xidation **I**is **L**Loss **R**eduction **I**s **G**ain Metals naturally Oxide as they are reactive Unreactive metals like gold are too unreactive to react with oxygen. **Cheapest method (Reduction)** - Metal Oxides reacted with carbon, forming carbon dioxide and leaving behind a pure metal - Only works on the ones less reactive than carbon - (Zinc, Iron and Copper) from oxides Any more reactive use Electrolysis but is very expensive **Ores** - Metal rich compounds

Answer 19

**Redox reactions** - Reduction and oxidation take place at the same time Oxidation (Positive) - Loss of Electrons Reduction (Negative) - Gain of electrons **Oil Rig Acronym** **O**xidation **I**is **L**Loss **R**eduction **I**s **G**ain Mg + H2 -> Mg 2+ atoms +H2 **Displacement Reaction** - A more reactive metal displacing a less reactive one Calcium + Iron Sulfate -> Calcium Sulfate + Iron Calcium Displaces Iron It will lose 2 electrons to bond with the negatively charged sulfate **Half Equation** Ca -> Ca+2 + 2e- Ca - Calcium E - Electron

Answer 20

**Equipment** - Beaker - Electrolyte (Free to move Ions) - Electrodes - Wire - Power supply like a battery **Soluble** - Dissolve it in water **Insoluble** - Melt it to get a molten liquid - only way to ensure they can move around **Electrodes** - Solid Conductors - Right is the positive electrode known as the anode - Left is the negative electrode known as the cathode - Usually **inert** carbon meaning it is unreactive and will not take part in the reaction **Electrolysis** - Splitting up with electricity Negative Ions attract to **Anode** while positive ions attract to **Cathode** Once there they will **discharge** and become normal atoms then pairing up forming a gas or solid Anode - Oxidized - Positive - Negatives attracted Cathode - Reduced - Negative - Positives attracted

Answer 21

Works on all reactivity series however is only economical for the ones **more** reactive than carbon Solid (Ions are fixed) so isn't an electrode - Purify raw ore - Mix the aluminum with **cryolite which lowers the melting point** - Now set up the equipment Purify, then mix with cryolite then electrolyze

Answer 22

**Soluble** - Dissolve them in water **Insoluble** - Melt into molten **Always Present** H20 -> H+ + OH- **Rules** - Cathode will attract negative Ions - Will only discharge one of the ions - Ion of the least reactive element will be discharged - Positive Anode if Halide is present than that will be discharged - If no Halide is present it will be the Hydrogen that gets discharged

Answer 23

**Group 7 known as Halogen** **Group 0 Known as Nobel gasses** **Halogens** - Fluorine - Poisonous yellow gas - Chlorine - Less reactive but poisonous - Bromine - Red poisonous - Iodine - Poisonous purple vapors - Diatomic molecules (2 atoms) Boiling point and melting point increases further down you go same as Nobel gasses reactivity decreases further down you go as the outer most shell is further away from the nucleolus so the attractive force is weaker Ionic Bonds with metals known as **Halide** Fluoride, chloride ,bromide ,iodide

Answer 24

**Rate of reaction** - Refers to the speed that reactants turn into products Rates can be very different, some within seconds other over years To measure the rate of reactants we need to measure, how fast products are formed or how fast the reactants are used up Rate of reaction = Quaintly of reactants used / Time taken Rate of Reaction = Quantity of products formed / Time Taken Grams and Cms

Answer 25

**Factor** - Temperature - Surface area - concertation/pressure - catalyst **Collison theory** - For particles to react they collide with each other with sufficient energy (Activation Energy) 1- Amount of energy the particles have 2- Frequency of the collisions Higher tempreture = quicker rate of reaction More surface area = Quicker rate of reaction More pressure - quicker rate of reaction Catalyst = Increases rate of reaction

Answer 26

Concentration of reactants and products wont change any more - is constant doesn't mean that they are the same Reversible reaction can both take place at different rates Must be in a closed system as to not lose and products or reactants Equilibrium - Both reactions still happening - Canceling out each other When there is more products the equilibrium lies to the **right** when more reactants the equilibrium would lie to the **left** Adding heat would move it to the right if cooled would go back to the left

Answer 27

Position of equilibrium during a reversible reaction position will try to counter act the change **Negative shows it is exothermic forward reaction** **Endothermic is backwards if negative** **Decreasing temperature **would move it in the **exothermic** direction If more products than reactants the position will move to the right If added **pressure the position** will move to side with **least molecules** If added concentration then the equilibrium would shift to the opposite side Negative Joules = Exothermic Positive Joules - Endothermic

Answer 28

**Chemical Analysis** - The instruments and methods used to identify, separate and quantity results **Purity** - Something that contains only one type of compound or element - e.g pure water (H2O) Has specific boiling points used to identify unknown substances **Physical test** - Testing physical qualities **Chemical tests** - Using another chemicals **Impure** - Melt and boil over a range of temperature dependent on what is in the mixture - Usually lowers the melting point but increases the boiling point **Formulations** - Mixtures that have been prepared using a specific formula - Precise amounts of different components - Have a particular function - Fuels, medicines, cleaning agents, food and drink, alloys and fertilizer

Answer 29

**Tests for** Chlorine oxygen hydrogen carbon dioxide **chlorine** - Requires test tube and sample gas - Blue litmus paper and dampen it - **If chlorine is present will turn from blue to white ** - Wear mask or do in a fume cupboard **Oxygen** Glowing splint - Glowing splint without a flame - **If gas is present will relight the splint** **Hydrogen** Lighted splint in mouth of test tube - Squeaky Pop - Splint should be burning - **A squeaky pop should be heard if hydrogen is present ** **Carbon dioxide** Bubble through limewater - Limewater test bumbling the gas sample - **if gas is present the water will go cloudy**

Answer 30

**LCA** Analyze the different stages in a products life cycle to asses the effects on the environments 1. Extracting and processing the raw materials 2. Manufacturing and packaging the product 3.using your product 4.disposing of product **Stage One: Extracting** - Can damage trees and wildlife to achieve the item - or during fracing - a lot of pollutants released **Packaging and manufacturing** - energy used - waste products - pollutuion **Usage of product** - How much damage it does in its life - How long it is used for and how many times it will be used **How its disposed** - Using landfill may have chemicals or take up land for the environment - May release pollutants - Take into account energy used **Limitations of LCA** - Involves a lot of steps and is hard to quantify all of them - Asses the harm of each step in comparison to others - Companies can manipulate to look more favorable

Answer 31

**Potable water** - Water that is safe to drink - Doesn't mean it is pure water - pH of 6.5 and 8.5 - No microorganisms - Levels of dissolved substances must be fairly low **Fresh water** Countries with access to fresh water comes from rainwater usually Collects as surface or ground water Surface water - Lakes - Rivers Ground water - Aquifers Requires treatment 1. Pass it through wire mesh 2. Pass it through bed of sand and gravel to remove smaller bits 3. sterilize it to kill and microbes - chlorine gas - UV light - Ozone **Desalination** - Extract potable water from sea water **Distillation** and **reverse osmosis** are very expensive **distillation** - same process as simple distillation **Reverse osmosis** - Passed through a membrane only allowing the water molecules to get through

Answer 32

** 3 main sources** - Domestic - goes to sewers - Agricultural systems - Industrials All has to be treated to make it safe before its disposed off. Remove any Organic matter and harmful microbes **How sewage treatment actually works** 1. Screening the sewage, removing anything large 2. Let it sit in a settlement tank to undergo sedimentation Sludge will since and go to a separate tank while the effluent (Top) will go to its own tank effluent is under aerobic conditions Sludge is under anaerobic conditions 3. Break down all organic matter, Relying on biological breakdown. effluent water is now safe Anaerobic digestion used as a fertilizer as well as a gas source

Answer 33

**Mixture** - Two or more substances - NOT Chemically bonded **Compounds** - Two or more substances - Chemically bonded

Answer 34

Salt made by the neutralization of an acid with a base - Measured amount of acid 40 ml - Gentle heat using tripod, gauze and budson burner - Solid base required - Alkalis or anything that makes an acid into a salt neutralizes it - Add an excess of copper oxide to neutralize all of the acid - Forms soluble salt copper oxide - Test by adding till base appears at the bottom of the beaker - Filtration using filter paper and funnel - Pure solution Evaporate water out of the solution - Using a water bath - Water evaporates making crystals

Answer 35

**Method** - Fill beaker 50 cm of Chemical you want - Electrodes are submersed but not touching crocodile clips - Positive terminal means anode - Negative means cathode - Positive means gas - Blue litmus paper shows positive test for chlorine - Cathode means gas **Example** At the anode 2CL- -> Cl 2(g)+ 2e- Cathode Cu2+ +2e- -> Cu (s) Oxidation Is Loss Reduction Is Gain If metal is more reactive than hydrogen → hydrogen gas is produced. If metal is less reactive than hydrogen → metal is produced.

Answer 36

Potassium → Sodium → Calcium → Magnesium → Aluminum → Hydrogen → Copper → Silver → Gold

Chemistry Flashcards

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