Unit 1 Flashcards
Whats a standard solution
Its a solution with an accurately known concentration.
What does the pH scale measure
The pH scale measures the acidity or alkalinity of solution. A pH less than 7 is acidic. Alkalis dissolve in water to give a pH greater than 7. A pH equal to 7 indicated a neutral solution.
Name 3 acids and their formula
Hydrochloric acid-HCl
Sulfuric acid-H2SO4
Nitric acid-HNO3
Name 3 alkalis and their formula
Sodium hydroxide-NaOH
Calcium Hydroxide-Ca(OH)2
Lithium hydroxide-LiOH
What happens when an alkali is diluted
The concentration of OH- ions is decreased and the pH decreases towards 7.
What happens in water and neutral solutions
The concentration of hydrogen ions id equal to the con of hydroxide ions
Whats neutralisation
This is the reaction of an acid with a base that results in the pH moving towards 7.
2 example equations of neutralisation
Acid + alkali —-> salt + water
Acid + metal oxide —-> salt + water
How do you name a salt
The metal ion from the alkali replaces the hydrogen ion from the acid (alkali to front, acid to back)
What is the salt name ending for hydrochloric, sulfuric and nitric acid
Chloride
Sulfate
Nitrate
What happens during neutralisation
The H+ ion from the acid joins with the OH- ion from the alkali
What do non-metals form
Negative ions
What do metals form
Positive ions
What equipment do you need to make a standard solution
Volumetric flask, Beaker, Wash bottle, 3 d.p balance, stirring rod, spatula, pipette dropper, deionised water, weighing boat, funnel
Whats the method to making a standard solution
•first calculate mass of solute needed
•Then weigh it into weighing boat using 3 d.p balance
•Then transfer into beaker ensure all solute is transferred by rinsing the weighing boat with distilled water
•Ensure all of the solute has been dissolved then swirl the solution
•Once dissolved transfer into volumetric flask DONT SPILL
•Then rinse to ensure none of the original solution is left do this 2-3 times
• Once rinsed place stopper
•gently shake
•Then fill up volumetric flask with distilled water until the bottom of the meniscus is touching the line
What factors affect the reaction rate
•Temperature
•Concentration
•Particle size
•Use of catalyst
Whats the collision theory
For a reaction to occur, the particles that are reacting must collide with each other. Only some collisions take place cause a chemical reaction to happen. These are called successful collisions. The greater the number of successful collisions, the faster the rate of reaction.
What are the three different ways to monitor the rate of reaction
•3dp balance
•Gas syringe
•Measuring cylinder
How do you calculate average rate of reaction
Average rate= Change in quantity/change in time
Whats an independent variable
The variable that is being changed during the experiment.
Whats an dependent variable
The variable being tested/measured during the experiment.
Whats an electrons mass, charge and location
Mass:Approx 0
Charge:-1
Location:Energy level
Whats a protons mass, charge and location
Mass:1 amu
Charge:+1
Location:Nucleus
Whats a Neutrons mass, charge and location
Mass:1 amu
Charge:0
Location:Nucleus
Whats an atoms overall charge
Every atom has no overall charge
What are horizontal and vertical lines called on the periodic table
Horizontal-Periods
Vertical-Groups
What are four major signs of a chemical reaction
•colour change
•energy produced
•Gas released
•New substance formed
What are the properties of alkali metals (group 1)
They are soft metals with low density that react rapidly with water producing an alkaline solution and hydrogen gas. The metals become more reactive as you go down the group
What are the properties of the alkaline earth metals (group 2)
They are slightly less reactive, harder and denser than group 1
What are the properties of the halogens (group 7)
Fluorine and chlorine are gases. Bromine is one of only two liquid elements. Iodine is solid. They exist as diatomic molecules-they have two atoms in each molecule. As you go down the group the halogens become less reactive.
What are the properties of the noble gases (group 0)
They are very unreactive and exist as individual atoms
What are the properties of the transition metals
They are found between group 2 and 3. Examples are iron, copper and gold. They are generally quite dense and many form brightly coloured compounds.
What does the atomic number tell us
How many protons that element has.
Whats the maximum amount of electrons the first energy level can hold
Two electrons
Whats the maximum amount of electrons the other energy shells can hold
Maximum of 8 electrons
Whats the mass number
The mass number tells us the number of protons and neutrons in an atom
Whats an isotope
An isotope are atoms with the same atomic number but a different mass number
How to atoms form a stable electron arrangement
Atoms can either lose, gain or share electrons
Whats a covalent bond
A covalent bond is a shared pair of electrons between atoms of two non-metal elements.
What are the 7 diatomic elements
Iodine, Bromine, Chlorine, Fluorine, Oxygen, Nitrogen, Hydrogen
What structure does a diamond have
Tetrahedral structure
What are ionic bonds formed between
Ionic bonds formed between a metal and a non-metal
What structure do Ionic compounds form
Lattice Structure
What happens to the outer electrons in metallic bonding
They become delocalised (free to move)
What are the properties of Ionic lattice
Ionic lattice have high boiling and melting points, they are solid at room temperature and they only conduct electricity when molten or in solution.
What are the properties of covalent network
In covalent network the boiling and melting points are very high, they are solid at room temperature and they never conduct electricity except graphite
What are the properties of Discrete Covalent molecules
Discrete covalent molecules have low melting or boiling points, they are liquid or gas at room temperature and they never conduct electricity
What are the properties of Metallic
Metallic generally have high melting and boiling points, they are solid at room temperature (except mercury which is liquid) they conduct electricity
Whats electrolysis
Electrolysis is the breaking up of an ionic solution using electricity
What are alkalis
They are soluble bases. An alkaline solution can be formed when a metal oxide is dissolved in water
How is an acidic solution formed
They are formed when a non-metal is dissolved in water
Why do we carry out titration experiments
Titration experiments can be carried out to accurately measure the volume of substances that react in chemical reactions. This technique is commonly used in neutralisation reactions and can also be used to calculate an unknown concentration
How do you carry out a titration experiment
- If the sample is solid its weighed using an accurate balance, this is then dissolved to make up a known volume of solution
- A pipette is used to measure accurately a volume of this solution. A safety pipette filler is used to draw solution into the pipette. This is emptied into a conical flask.
- A few drops of indicator may be added to the conical flask. This will show a change of colour when the titration is complete.
- A second chemical is places in the burette. The other solution is of a chemical that will react with the synthesised chemical sample in the conical flask. Often the solution in the burette is an acid acid of a precise known concentration
- The solution from the burette is run into the conical flask. The solution is added one drop at a time, with swirling to mix the solutions as the end-point is approached. Eventually, a colour change shows that the correct amount has been added to react completely with the synthesised chemical in the sample.
- The volume of solution added from the burette is noted. The titration results can then be used to calculate the amount of the synthesised chemical in the sample, and therefore find its purity.
What equipment do you use for titration
Burette, Conical flask, Pipette filler and Pipette
