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Chemistry C3 GCSE

Chemistry C3 GCSE (Sorry about Lack of punctuation!)

QuestionAnswer
Do endothermic reactions release or use energy They use energy to form bonds
What is a titration used for To measure the exact quantities of chemicals needed to neutralise each other, also it can be used to determine the concentration of an unknown substance
How do you calculate the mol of the known substance Mol = C x V = Concentration X Volume (In dm3 (Or divide cm3 by 1000))
How do you calculate the mol of the unknown Concentration = M / V = Mol of Unknown/Volume of Unknown (In dm3)
What is a solvent It is the highest quantity of chemical within a substance
What is dissolving Dissolving is when 2 different quantities of chemicals diffuse together to make a homogenous solution
Learn the Water Cycle (Link on the other side)! http://www.enchantedlearning.com/wgifs/Watercycle.gif
As temperature/pressure increases, what happens to solubility For most solid solutes, as the temperature increases, so does the solubility. For pressure, as the pressure increases, so does the solubility.
Understand Solubility + Graphs! http://www.docbrown.info/page03/AcidsBasesSalts08.htm
What makes water hard and what causes scum The presence of Mg2+ and Ca2+, Part 2: The ions mix with sodium stearate to form stearates or scum
How can hardness be removed 1) Use Sodium Carbonate to precipitate the ions out (Make them insoluble) 2) Use an ion exchange column to ‘exchange’ Calcium and Magnesium ions for Sodium Ions, This means it must be kept topped up with salt, to keep it working
What are the advantages of hard water It can reduce the risk of heart disease, also Calcium helps to maintain strong teeth
What are the disadvantages of hard water It causes scum, it’s hard to make a lather with soap and shower gel, it reduces the life of products that use water (Showers, kettles, washing machines) and it reduces the efficiency of water using appliances (Up to 50%)
How is limescale formed within a boiler Calcium Hydrogen Carbonate dissolves into the water, this then thermally decomposes within the boiler, forming limescale
How are stalactites formed The Calcium Hydrogen carbonate dissolves into the water, as the water evaporates, the Calcium Hydrogen Carbonate is left behind, to make stalactites
Is domestic Water pure No
How is the energy released from fuel burning measured By using a calorimeter, its measured in Joules
How is the quantity of energy burned from fuel measured Q (Energy) = M (Mass of water in calorimeter) x Heat capacity of water (4,2 J per gram per Celsius) x Temperature change
Why would energy calculated from fuel burning with in a class room be different to an ‘official’ result in a lab The heat within the experiment within a classroom would escape into the surroundings
Is there a link between the size of the hydrocarbon, and the energy released Yes, as it gets larger (More Carbon and Hydrogen Bonds) the more energy is released
With a catalyst, what happens to the Activation energy It decreases
How are cations (positive Ions) tested for By using a flame test
Name the colour of the following cations: barium, Lithium, Sodium, Potassium, Copper and Calcium Barium – Green , Lithium – Red, Sodium – Yellow, Potassium – Lilac, Copper – Blue/Green, Calcium – Red/Green
Links http://www.school-portal.co.uk/GroupHomepage.asp?GroupID=554793 http://gcserevision101.wordpress.com/chemistry-c3/
How could Fe3+ be identified from testing? By adding NaOH and a Brick Red PPT being formed.
How could an NH4+ Ions Be detected? By adding NaOH, and no PPT being formed, then warming and the damp red litmus paper turning blue.
How could Fe2+ be identified? By adding NaOH and a Black PPT Forming.
If NaOH is added to a solution, and a White PPT Forms, what could the ions be? If you add more NaOH and the PPT disappears, what ion is present? 1) Al3+, Ca2+ or Mg2+. 2) Al3+
If Dil. HCl is added to a solution, and it fizzes, what ion is present? Carbonate (CO3^2-)
If you add dil. HCl to a solution and it doesn't fizz, then you add Barium Chloride, and it forms a dense white PPT, what ion is present? Sulphate (SO4^2-)
If AgNo3 and Dil.HCl is added to a solution and a White PPT is formed, what ion is present? Cl-
If AgNo3 and Dil.HCl is added to a solution and a Cream PPT is formed, what ion is present? Br-
If AgNo3 and Dil.HCl is added to a solution and a Yellow PPT is formed, what ion is present? I-
If you warm a solution with NaOH and the ammonia test is negative, then you add Al Powder, and it turns blue, what ion must be present? NO3-
What are the 4 main stages of water being purified for tap use? 1) Big Filters to remove leaves + Large Bugs 2) Aluminium Sulphate is added to clump small particles together + sedimentation to remove these particles. 3) Chlorine gas is added to kill bacteria and microbes that are left. 4) pH check is run.
If the water coming out of a purification plant is too high, what should the company do to the water supply? They should stop the water supply immediately and try to fix the problem as soon as possible.
What scientific 'law' did Newlands come up with? The law of octaves (A periodic Table based on repeating patterns of 8, although the structure of an atom (shells etc.) hadn't been theorized yet.
What theory did Döbereiner come up with? The theory of 'triads' or groups of 3 elements, where the middle one was an average of the other 2. This was discounted as a relevant theory as it didn't leave gaps for undiscovered elements.
Who came up with the modern periodic table? Dmitri Mendeleev
Why is it called the periodic table? Because the chemicals with similar properties appear at even periods (Intervals).
For the initial periodic tables that strictly followed the order of atomic masses, why was this wrong? Some of the elements had properties which made them be better suited if they moved into other groups.
When were electrons, protons and neutrons discovered? In the early 20th Century.
Elements in the same group have what? The same number of electrons in the highest energy level (Shell)
The higher the energy level, the ___ it is for electrons to be gained, and the ___ it is for electrons to be lost. The higher the energy level, the HARDER it is for electrons to be gained, and the EASIER it is for electrons to be lost.
Do the metals in group 1 have a high or a low density? Low density (The first 3 are lighter than water)
Group 1 elements react with Non-metals to form __ compounds in which the metal ion carries a charge of ___.The compounds are ___ solids which dissolve in water to form ___ solutions Group 1 elements react with Non-metals to form IONIC compounds in which the metal ion carries a charge of +1.The compounds are WHITE solids which dissolve in water to form COLOURLESS solutions
When group 1 elements react with water, what is formed? Hydrogen and Alkaline Solutions
In group 1, the further down the group the element is, the __ reactive the element is and the ___ the melting and boiling points are. In group 1, the further down the group the element is, the MORE reactive the element is and the LOWER the melting and boiling points are.
Do group 7 elements have coloured vapours? Yes
The halogens consist of single or pairs of atoms? Pairs (Br2, Ar2 etc...)
Group 7 elements form ___ salts in which the chloride, bromide or iodide ion (halide ion) carries a charge of ___. Group 7 elements form IONIC salts in which the chloride, bromide or iodide ion (halide ion) carries a charge of -1.
Group 7 elements form __ compounds with other non-metallic elements. Molecular
In group 7, the further down the group the element is, the __ reactive the element is and the ___ the melting and boiling points are. In group 7, the further down the group the element is, the LESS reactive the element is and the HIGHER the melting and boiling points are.
Can a more reactive halogen displace a less reactive halogen from an aqueous solution of its salt? Yes
Are all the transition elements non-metals or metals? Metals.
With the transition elements, how many electrons must be in the 4th shell in order for the 3rd shell to accept up to 18 electrons? 2.
Compared to Group 1 elements, transition elements have ___ melting points (Apart from ___) and ___ densities. They also are ___ and ___. They are much __ reactive and do/do not react as vigorously with ___ or ___. Compared to Group 1 elements, transition elements have HIGHER melting points (Apart from MERCURY) and HIGHER densities. They also are STRONGER and HARDER. They are much LESS reactive and do/do not react as vigorously with OXYGEN or WATER.
Do transition elements form white or coloured compounds? Coloured
Are Group 1, group 7 or transition elements used as catalysts? Transition elements.
Try to think of as many advantages of instrumental analysis as possible. Some examples: Fast Results, accurate, a small sample is required and it is sensitive.
Atomic absorption spectroscopy does what? It records the concentration of a particular metal in a liquid.
A mass Spectrometer does what? It measures the mass of different molecules to allow them to be compared.
What is chromatography used for? To separate compounds from a mixture.
What is gas-liquid chromatography used for? To separate compounds which are easily vapourised.
What is high performance chromatography used for? To separate compounds in solution.
What is gel permeation chromatography used for? To separate compounds according to the size of their molecules.
What is ion-exchange chromatography used for? To separate compounds containing differently-charged particles.
After chromatography tests, how are the chemicals identified? They are compared to results which have been gathered from substances.
What is gel electrophoresis used for? To compare DNA, possibly from a crime scene or to help identify people.
When a hot, saturated solution cools, what happens? The excess solute will separate from the solution.
Does the solubility of gases increase or decrease as the temperature decreases? As the temperature decreases, their solubility increases
Dissolving carbon dioxide into water at high pressure makes what? Carbonated water (Fizzy water), when the pressure is decreased, it starts to fizz.
Dissolved oxygen is essential for which animals? Aquatic animals.
How does water become hard? When the water comes into contact with rocks containing Calcium or Magnesium Ions
How can the taste/quality of tap water be increased? By passing it through a water filter system (BRITA) which contain filters made of carbon, silver and ion exchange resins.
How can pure water be made? By distillation
How do catalysts alter the Activation energy? They lower it.
What is the term for measuring the energy given off when something is burnt? Calorimetry
1 calorie = how many Joules? 4.2 joules.
What types of food GENERALLY produce HIGHER amounts of energy? Foods that are high in Carbohydrates, fats or oils.
Eating food which contains more energy than your body needs can lead to what? Obesity.
During a reaction, energy must be supplied to ___ ___. Break bonds
During a reaction, energy is released when bonds are ___. Formed
In an _____ reaction, the energy released from forming new bonds is ___ than the energy needed to break existing bonds. In an EXOTHERMIC reaction, the energy released from forming new bonds is GREATER than the energy needed to break existing bonds.
In an ___ reaction, the energy required to ____ bonds is ___ than the energy needed to form new bonds. In an ENDOTHERMIC reaction, the energy required to BREAK bonds is GREATER than the energy needed to form new bonds.
Organic compounds ___ or ___ when heated in air Organic compounds BURN or CHAR when heated in air
Unsaturated organic compounds which contain double carbon-carbon bonds do what to bromine water? They decolourise it.
What is a proton donor? An acid
What is a proton reciever? An Alkali/base
Normally, what must be present for a substance to act as an acid or base? Water.
Acids produce __ ions in aqueous solutions. Hydrogen (H+)
Alkalis produce ___ ions in aqueous solutions Hydroxide (OH-)
A strong acid or alkali is one that is completely __ in water. Ionised
3 examples of strong acids and 2 examples of strong alkalis are: Hydrochloric, Sulfuric and nitric acid. Potassium or Sodium Hydroxide.
A weak acid or alkali is ___ ionised in water. Partially
3 examples of weak acids and 1 example of a weak alkali are: Ethanoic, Citric and Carbonic Acids. Ammonia solution is a weak alkali.
For a strong acid/strong alkali titration, what indicator would you use? Any acid-base indicator
For a weak acid/strong alkali titration, what indicator would you use? Phenolphthalein Indicator
For a strong acid/weak alkali titration, what indicator would you use? Methyl Orange
Water is rivers, lakes and the oceans is ___ by the heat of the ___. This forms water vapour the rises in the ___ and cools so that it condenses to form ___. The water droplets in the clouds join together to make ___. Water is rivers, lakes and the oceans is EVAPORATED by the heat of the SUN. This forms water vapour the rises in the ATMOSPHERE and cools so that it condenses to form CLOUDS. The water droplets in the clouds join together to make RAIN.
Most __ compounds are soluble in water. Ionic
Some __ substances are soluble in water. Molecular
Many ___ compounds are insoluble in water Covalent
Created by: DHSBBen