Chemistry flashcards

Solids

fixed volume, Tightly packed, regular arrangement -> lattice. Vibrate in place, don't move freely

Liquids

Close together, slight separation, irregular arrangement, slide past each other

Gases

Spread apart, totally irregular arrangement, very far apart move rapidly and collide with container walls

Melting

the process of change from a solid to a liquid. Particle absord heat and kinetic energy increases. The dchange happens at M.P

Boilling

The process of change from liquid to gas as particles' kinetic energy increases and the liquid changes rapidly gas molecules escape the body of water.

Condensing

Gas to liquid, particle lose energy, occur in arange of temperature

Freezing

liquid to solid happens at F.P

Evaporation

turns liquid to gas, occurs in the surface of liquids, change of stae from liquid to vapour under B.P

Affect of temperature on volume of gas

When temperature increases particles move faster they collide with the container wall pushing it as a result volume of gas increase

Affect of pressure on gas volume

Pressure increase gas takes up less space volume decrease

Kinetic particle theory

Overview:

+Matters are made up of particles

+Particle mare moving al the time, movement and arrangement are diffrent for 3 types of matter.

+The more gas particles collide with the container walls the more pressure

Heating curve

A heating curve is a graph that shows the temp against the change states 📈

Heating curve Phase 1

A the temp rises, particles gain more energy, overcoming the force of attraction between particles 🌡️

Heating curve Phase 2 (Melting)

The line becomes flat, aka MP, where the change of state happens (melting) ➖

Heating curve Phase 3

Once the solid melted and turned into a liquid temperature increase again, as energy increase further and the force of atratction is broken again 💧

Heating curve Phase 4 (Boiling)

The line becomes a plateu as liquid boils the atraction between liquid particles is being broken and the change of state happens (AKA B.P / boiling) ♨️

Heating curve Phase 5

The temp increase again when liquid became gas ☁️

Cooling curve Phase 1

At this part the substance is in a gaseous state, but the tem decreases as energy is lost 📉

Cooling curve Phase 2 (Condensation)

The line of plateau indicates change of state as new bonds formed between gas particles, turning them into liquid through condensation (condensation point) 🌧️

Cooling curve Phase 3

As the temperature decreases further liquid particles formed new bonds 💧

Cooling curve Phase 4 (Freezing)

The line becomes horizontal freezing point is reached and changes of state happens (AKA freezing point / freezing) 🧊

Cooling curve Phase 5

Tempearature further decreases as the solid loses more heat ❄️

Affect impure substance on heating curve

+ Melting point is lower than pure -> disrupt solid structure

+ Boilling point increases -> harder to provide energy for the substance as impure block the way

Diffusion

The process in which particles move from higher conc. To lower conc. As a result of random motion of the particles 🌬️

Diffusion in liquid

+ Particles is broken down in the liquid + Particles move randomly and move from higher concentration to lower concentration + Particles collide with each other making the particles move in a random motion + Particles stop diffusing when an equilibrium happens 🍵

Diffusion of gases (Image Details)

Liquid bromine is highly volatile. Gases diffuse to fill all the space available to them. Atoms or molecules in gases move at high speeds and they collide with each other. Frequent collision slow down the overall rate of diffusion. 💨

Mass and Diffusion (Image Details)

Particles of gases travel at different speeds. 2 pieces of cotton wool soaked, one in ammonia solution and one in hydrochloric acid. Ammonia particles and hydrogen chloride diffuse along the tube. White rings forms when the chemical reaction takes place at the side where the gas has more mass as ammonium travel faster

Movement and arrangement change of water particles 10 degrees celcius -> -10 degrees celcius

Water partcles starts as a liquid the particles in water are touching close together with irregular arrangement and sliding onto each other as the water is cooled to -10 degrees celcius the water particles is arranged regularly and the particles vibrate in position

Atoms

the Smallest unit of a matter 🔬

Elements

Pure substance that cannot be further seperated by chemical means and made of particles with the same number of protons

Compounds

A substance that are made of 2 or more substances chemically bonded together 🔗 in a fixed proportion

Mixture

Two or more substances that are mixed together but are not chemically bonded could be separated by physical means 🥗

Atomic Structure (from image)

Atoms consist of a central nucleus containing positively charged protons and neutral neutrons, surrounded by negatively charged electrons orbiting in shells. ⭕

Isotopes

different atoms of an element with different mass number and neutrons in the nucleus but the same number of proton and electrons meaning the same chemical properties ⚖️

Isotopes (Chemical Properties)

Isotopes have the same number of valence electrons so all isotopes have the same chemical properties 🧪

Isotopes (Physical Properties)

The difference between isotopes is the neutrons which are neutral particles within the nucleus and add mass only The difference in mass affects the physical properties, such as density, boiling point and melting point 🌡️,

Ionic Bond

is a strong electrostatic attraction between oppositely charged ions & between metal and non metal 🧲

IONS

Ions are charged particles mad from an atom, or group of atms, by Loss or gain of electrons ➕➖

Valency

The number of elctron its atom lose, gain or shares, to form a compound 🤝

Valency Rules

Metal = # Group, Non - metal = 8 - Group # 🔢

Compound ions

Some covalent compounds have charge -> Compound ions ⚛️

Ionic groups made with covalent bonds (Polyatomic ions definition)

Ions that are made up of two or more atoms joined together by covalent bonds, but which have an overall electrical charge

Properties of Ionic compound (Physical)

Ionic compounds are solid at R.T.P, They form lattice structure, High M.P & High B.P Held by the strong electrostatic force of attraction with a regular lattice arrangement of alternating positive and negative ions, Soluble in water -> Good electrical conductivity when aqueous/molten & poor conductivity as a sold 🧊

Covalent bonds

formed when a pair of electrons is shared between two atoms leading to a noble gas/ octet formation & Between nonmetals and non metal ☁️

Properties of Covalent compound (Physical)

liquid or gas at RTP, Formed of simple molecules and atoms joined together by covalent bonds, low M.P & B.P -> Not much energy is needed to break the weak intermolecular force, Covalent compounds have no ions present to carry current therefore do not conduct electricty 💧

Simple molecular substance

Consist of simple molecules with weak intermolecular force holding to each other 🫧

Giant Structures

Macromolecules, Ionic Lattices, Metallic lattices simpply put are compound with large structure and strong bons between each molecules 🏗️

Diamond 💎 (Structure)

Diamond are made of carbon atoms, Each carbon mol. Is bond with 4 others, Tetrahedral structure 💎

Diamond 💎 (Properties)

Non metallic -> Do no conduct electricity, Use as jewellry -> as it is colouless shape which is transparent crystals, Drill bits -> hardest natural substance on earth ⛏️

Graphite ✏️ (Structure)

In graphite is is formed in hexagonal shape in each layer with strong covalent bonds in each layer, Each carbon atom formed a triple bond with one free electron 📝

Graphite ✏️ (Properties)

Conduct electricity, Soft, slippery -> lubricants ⚙️

Metallic Bond

The electrostatic attraction between the positive ions in a giant metallic lattice and the "sea" delocalised electron 🌊

Metallic Bond Structure (Image Description)

A regular arrangement (giant lattice) of closely packed positive metal ions surrounded by a "sea" of freely moving, delocalized electrons that can move between the ions. 🔋

Properties of Metals

Conduct electricity -> Free electrons can carry current, Malleble -> easily bent and shaped, slide on each other to form new bond when bent, Ductile 🔨

Formulae

Group of letters and number that show which atoms/elements in a molecule 🔤

The drop-down method for compounds

Used to determine the formula of a compound by crossing over the valencies/charges of the ions ↘️

Rules of thumb for naming elements - Metal First

If there is a metal in the compound, it is named first (e.g. Magnesium Oxide) 🥇

Rules of thumb for naming elements - Multiple Ions

Where a metal can form more than 1 ion, then the name indicates which ion is present (e.g. Iron (II) chloride) 🔢

Rules of thumb for naming elements - 2 Elements

Compounds containing only 2 elements have names ending in -ide (e.g. Sodium chloride or Mg3N2) ✌️

Rules of thumb for naming elements - Compound Ions

Compounds containing a compound ion have names ending in -ate (e.g. Calcium Carbonate) ⚛️

Rules of thumb for naming elements - Prefixes

The names of some compounds use prefixes to tell you the number of that particular atom in the molecule. (useful if 2 elements form more than 1 compound) (e.g. Carbon monoxide and Carbon dioxide) 🏷️

Molecular Formula

A formula that shows the actual number of atoms of elements in a molecule or compound 🧬

Reactant

The chemical(s) you start with before the reaction. Written on left side of equation. ⬅️

Product

The new chemical(s) formed by the reaction. Right side of equation. ➡️

Law of Conservation of Mass

In a chemical reaction, matter is neither created nor destroyed. In other words, the number and type of atoms going INTO a reaction must be the same as the number and type of atoms coming OUT. We never change one element into another element (that is nuclear physics, not chemistry!). If an equation obeys the Law of Conservation, it is balanced. ⚖️

Rules for balancing an equation

1. Matter cannot be created or destroyed. 2. Subscripts (the small number e.g. H2) cannot be added, removed, or changed. 3. You can only change coefficients (the big numbers, e.g. 2Na). 4. Coefficients can only go in front of chem. formulas NEVER in the middle of a formula (e.g. 2NaCl never Na2Cl). 🔢

Balancing an equation - Extra Tips

Try balancing big formulas first; save free elements for last. If the same molecular ion (e.g. SO4 2-) appears on both sides of the equation, you can usually treat it as one unit. There is no one particular way to balance equations. Some equations are harder to balance than others, and might require some creativity to solve. 💡

State Symbols

s = solid, l = liquid, g = gas, aq = aqueous solution (dissolved in water) 💧

Ionic Equations

The simplifies chemical equations where spectator ions are eliminated and only include elements that take part ⚡

Net Ionic Equation Steps

1. Write Balanced Chemical Equation. 2. Write Complete Ionic Equation (break aqueous compounds into ions). 3. Cancel the spectator ions that appear on both sides of the arrow. 4. Write the final Net Ionic Equation. 📝

Ar

is the average mass of of all isotopes of elementstaken into account the percentage and abundance 📊

A mole always counts the basic unit that repeats in the substance natural structure

+ if it is made of single atoms, we count atoms

+ if it is made of bonded groups, we count molecules + if it is a lattice, we count formula units 📦

Formula unit

is a chemical formula for an ionic compound and represent the simples ratio 🧱

Molar mass

the mass, in grams, of 1 mole of a substance ⚖️

Avogadro constant

the number of particles in 1 mole of a substance 🔢(6.02 times 10 to the power of 23)

Limiting reactant

the reactant that is not in excess 🛑

Reaction Calculation Bridge

Mass of product -> Moles of product -> Use ratio -> Moles of reactents -> Mass of reactents

Mass Formula Triangle

Moles = mass / Mr, Mr = mass / moles, Mass = moles x Mr 🔺

Molar Gas Volume Triangle

Volume = no. of moles x molar volume 🎈

Concentration Formula Triangle

Moles = concentration x volume 🧪

Enthalpy

Transfer of thermal energy during a chemical reaction 🌡️

Activation energy

The minimum energy that colliding particles have to react ⚡

Bond energy

The energy required to break a bond 🔗

Exothermic reaction

A chemical reaction that transfer thermal energy to the surrounding ♨️

Exothermic Pathway diagram

-> Overall energy change = negative as ebergyis transfer to the surroundings, delta H = - -> y -> energy, x -> progress of reaction -> Every reactants will need to break there bond before a synthesis or decomposition reaction could really happen that part is called Ea thi is where bonds are broken in the substance 📉

Exothermic bond energy

Bonds are formed 🤝

Endothermic reaction

A chemical reaction that absorb thermal energy to the surrounding ❄️

Endothermic Pathway diagram

-> The overall enthalpy change is positive as energy is absorbed as product energy is higher, delta H = + 📈

Endothermic bond energy

Bonds are broken ✂️

Physical Changes

-A change in physical state of a substance that does not involved in chemical reactions + Can separate with physical means + Reversible + No new substances are made -> E.g: Changing state, mixture made, Dissolving substances 🧊

Chemical changes

-Changes which a new substance is formed -> New properties and chemical composition + irreversible + Energy changes 🎇

Concentration of solution

+Increasing the concentration -> More reactant particles in the same volume -> more frequent collisions between reactant particles -> More successful collision -> Increase rate of reaction 💧

Change of gas pressure

Increase in gas preassure More reactant particles in the same volume -> more frequent collisions between reactant particles -> More successful collision -> Increase rate of reaction 🎈

Change of Surface Area

Increase surface area -> More exposed reactent particles -> More frequent collisions -> Increase rate of reaction 🔲

Change in Temperature

Increase in temperature -> Increase in kinetic energy of reactent particles -> More frequent collisions between reactent particles -> increase successful collisions-> Increase in rate of reaction 🌡️

Presence of catalysts

Adding catalyst -> increas reate of reactions by lowering activation energy -> increase reactent particles with sufficient energy for successful collision 🏎️

Collision theory - Rule 1

+ For chemical reaction to happen reactent particles must collide successfully 💥

Collision theory - Rule 2

+ The must be enough energy for collison to be succesfulalso known as Activation energy ⚡

Collision theory - Rule 3

+ The more frequent successful collision the faster the rate of reactions ⏱️

Periodic Table Columns and Rows

Vertical columns to Groups = # number of valence e-. Horizontol rows to periods = # shells ↕️