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Year 11 100 Science4 External Credits
AS90944Ms Gibellini
Aspects of acids and bases will be selected from:
Atomic structure
electron arrangement of atoms and monatomic ions of the first 20 elements (a periodic table will be provided)
ionic bonding
names and formulae of ionic compounds using a given table of ions.
Properties
acids release hydrogen ions in water
reactions (of acids with bases) to form salts.
pH and effects on indicators.
Rates of reaction and particle theory.
Uses
neutralisation
carbon dioxide formation
salt formation.
Acids and bases are restricted to HCl, H2SO4, HNO3, metal oxides, hydroxides, carbonates and hydrogen carbonates. Other acids may be included in examination questions. The names and formulae of any such acids will be given in the question.
Describe the structure of an atom
Discuss the key differences between the three sub-atomic particles
All matter is made up of atoms
Chemistry involves the rearrangement of atoms or groups of atoms
Recall the structure of an atom
http://www.youtube.com/watch?v=pV822HfqT44&feature=fvwrel
Atoms are made up of the following sub atomic particles:
Electrons negative charge
outside nucleus, in shells
constant motion
very very small (1/2000 of a proton)
Neutron No charge, neutral
Inside nucleus
Same size as proton
Proton Positively charged
Inside nucleus
A neutron walks into a restaurant and orders a couple of cokes.
As she is about to leave, she asks the waiter how much she owes.
The waiter replies, "For you, No Charge!!!"
Atoms have an overall neutral charge, therefore:
Number of protons = Number of electrons
Complete worksheets provided
Compete Scipad page 10: Atoms
Describe the atomic structure of a lithium atom
Explain how the particles within an atom contribute to its overall mass.
Describe the atomic structure of a lithium atom
Explain how the particles within an atom contribute to its overall mass.
Overall mass of an atom is made up of protons and neutrons, as the mass of electrons is negligible
Define the term ‘element’
Name and write symbols of common elements
Develop an understanding of the structure of the Periodic Table
Elements are made of only one kind of atom
◦ Gold is made of gold atoms
◦ Carbon is made of carbon atoms
◦ Hydrogen is made of hydrogen atoms
Elements have been put in order of:
Physical properties Chemical properties Atomic number Mass number Number of electrons in outer shell
on the Periodic Table of Elements
1) Hydrogen
2) Helium
3) Lithium
4) Beryllium
5) Boron
6) Carbon
7) Nitrogen
8) Oxygen
9) Fluorine
10)Neon
11) Magnesium
12)Aluminium
13)Silicon
14)Phosphorus
H
He
Li
Be
B
C
N
O
F
Ne
Mg
Al
Si
P
15)Sulphur
16)Chlorine
17)Argon
18) Calcium
19) Zinc
The less obvious ones:
1) Sodium
2) Potassium
3) Iron
4) Copper
5) Silver
6) Tin
7) Gold
8) Mercury
9) Lead
S
Cl
Ar
Ca
Zn
Na
K
Fe
Cu
Ag
Sn
Au
Hg
Pb
Element Song
Daniel Radcliff
20/01/2015
Mendeleev
The periodic table arranges all the elements in groups according to their properties.
Horizontal rows are called PERIODS
Vertical columns are called GROUPS
20/01/2015
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Fe Ni Cu Zn Br Kr
Ag I Xe
Pt Au Hg
Fact 1: Elements in the same group have the same number of electrons in the outer shell (this corresponds to their group
number)
E.g. all group 1 metals have __ electron in their outer shell
These elements have __ electrons in their outer shell
These elements have __ electrons in their outer shells
20/01/2015
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Fe Ni Cu Zn Br Kr
Ag I Xe
Pt Au Hg
Fact 2: As you move down through the periods an extra electron shell is added:
E.g. Lithium has 3 electron in the configuration 2,1
Potassium has 19 electrons in the configuration __,__,__,__
Sodium has 11 electrons in the configuration 2,8,1
20/01/2015
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Fe Ni Cu Zn Br Kr
Ag I Xe
Pt Au Hg
Fact 3: Most of the elements are metals:
These elements are metals
This line divides metals from non-metals
These elements are non-metals
20/01/2015
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Fe Ni Cu Zn Br Kr
Ag I Xe
Pt Au Hg
Fact 4: (Most important) All of the elements in the same group have similar PROPERTIES. This is how I thought of the periodic
table in the first place. This is called PERIODICITY.
E.g. consider the group 1 metals. They all:
1) Are soft
2) Can be easily cut with a knife
3) React with water
Metals on the _____
Non Metals on the ______
Rows tell us the number of electron shells an element has
Groups tell us the number of electrons in the outer shell
Complete Scipad page 11and 13
Determine the structure of an atom based on data from the periodic table
Draw the arrangement of electrons around any given atom
Use the electron arrangement of an atom to identify which group on the periodic table it belongs too.
What is the difference between Gold and Oxygen?
Elements are made up of one kind of atom only
Elements have been put in order of:
Physical properties
Chemical properties
Atomic number
Mass number
Number of electrons in outer shell
on the Periodic Table of Elements
Atomic Number:
Smaller number Number of protons Number of electrons
Atomic Mass or Mass Number:
Bigger number of the two Total number of sub atomic particles Number of protons + neutrons.
How do we work out the number of:
Protons = Atomic number
Electrons = Atomic number
Neutrons = Mass number – atomic number
Fill in first 5 columns of Elemental information sheet
Electrons arrange themselves in regular order around the nucleus depending on their energy.
Each energy level holds a different number of electrons:
◦ Level 1 – 2 electrons
◦ Level 2 – 8 electrons
◦ Level 3 – 8 electrons
Electrons fill from Level 1 shell, or the closet to the nucleus first.
Calculating electron arrangement using the periodic table:
Row/Period gives us the number of electron shells
Group tells us the number of electrons in outside shell
Eg Sodium – row 3 – three shells- group 1 – 1 electron in outside shell- electron arrangement = 2,8,1
Fill in columns 9, 10, 11 on elemental information sheet.
Draw dot diagrams for the first 5 elements H, He, Li, Be, B) (use dots for electrons, and draw shell lines in pencil, use blue pen for protons and red for neutrons)
Complete Scipad pages 12, 15, 16
http://lgfl.skoool.co.uk/content/keystage4/chemistry/pc/lessons/uk_ks4_atoms_periodic_table/h-frame-ns6.htm
Describe the role of electrons in chemical reactions
Describe how positive and negative ions are formed
Write the name and formula of common ions
Two atoms are walking down the street.
Says one atom to the other, "Hey! I think I lost an electron!"
The other says, "Are you sure??"
"Yes, I'm positive!"
Chemical reactions occur when atoms gain or lose electrons
The fewer electrons that are gained or lost the more reactive atoms are.
Atoms require their outer shells to be full in order to be chemically stable
Atoms either lose or gain electrons to get a full outer shell (2,8,8)
When atoms lose or gain electrons they become electrically charged and are then called ions
Gaining electrons (-ve) results in a ________ ion
Losing electrons results in a __________ ion
The number of protons (+ve) stays the same
E.g
Na Na+ + e-
Sodium atom sodium ion Free electron2, 8, 1 2, 8,
Cl + e- Cl-
Chlorine atom electron Chlorine ion2, 8, 7 2, 8, 8
The charge on an ion is called its valency.
Valency always has a sign (+ or -) and a numerical value. (although we don’t write 1)
Complete ion information on elemental sheet
Ionic compounds: Have equal numbers of + and – charges
Made up of metal and non metal
Named by the ions they contain
Metal part goes first, then non metal
If non metal ion is made up of two or more elements change end to ate,
SO4 – sulphate
only 1 element in non metal ion it ends in ide NaCl = sodium chloride
How do you know if an atom will gain or lose electrons?
Eg. Na 2,8,1- is it easier to lose one electron or gain 7?- Hence Na looses a negative electron to become: - Na+
Eg. Cl 2,8,7- is it easier to gain one electron or lose 7?- Hence Cl gains a negative electron to become: - Cl-
Information Na Be Cl
Atomic Number
Mass Number
Protons
Neutrons
Electrons
Electron Config.
Gain/Lose Electrons
+ve/-ve charge
Ion Formed
Ion electron config.
Protons:Electrons in Ion
Complete Scipad pages 17-19
Magnesium and calcium atoms both form ions with a charge of +2. Magnesium atoms form Mg2+ ions, and calcium atoms form Ca2+ ions.
Explain why magnesium and calcium atoms form ions with the same charge of +2. In your answer, you should: define an ion explain why atoms form ions identify the group on the periodic table where
the two atoms are found explain why both magnesium and calcium ions
have a charge of +2.
Definition of an ion:
An ion is an atom or group of atoms that have lost or gained an electron and therefore carry a charge.
Explanation of formation of ions:
If the outer shell (valence) of an atom is not filled, the atom is unstable. It will react to gain a full outer shell to become more stable, by either losing or gaining electrons and making it into an ion.
Identification of Group:
Magnesium and calcium are in the same group on the periodic table Group 2 – both have two electrons in outside shell.
Explanation of why both form+2 ions:
The atoms have the same number of electrons (two) in their outer shell. 2,8,2 and 2,8,8,2
Both Mg and Ca need to lose two outer electrons to become stable by having a full outer shell.
Each ion (Mg2+ and Ca2+) ends up with two less electrons(negative) than there are protons(positive) in its nucleus, so the ion has a charge of +2.
Describe ionic bonding
Use ions to write the name and formula of compounds
A sign outside the chemistry hotel reads "Great Day Rates, Even Better NO3
-'s"
Positive Ions Negative Ions
+1 +2 +3 -3 -2 -1
H+
HydrogenIon
Mg 2+
Magnesium Ion
Al3+
Aluminium Ion
N3-
Nitrite IonO2-
Oxygen ionCl-
Chloride ion
Li+
Lithium IonCa2+
Calcium IonFe3+
Iron III ionP3-
Phosphide ion
S2-
Sulphide ionBr-
Bromide ion
Na+
Sodium IonFe2+
Iron II ionPO3-
4
Phosphate Ion
CO2-3
Carbonateion
I-
Iodide ion
K+
Potassium Ion
Cu2+ SO2-4
Sulphate IonNO-
3
Nitrate ion
Ag+
Silver IonZn2+ HCO-
Hydrogencarbonate ion
NH+4
Ammonium Ion
Pb2+ OH-
Hydroxide ion
Ionic compounds have an overall neutral charge.
Therefore there must be equal numbers of positive and negative charges.
◦ Magnesium Nitrate Mg2+NO3-1
Mg+ Mg+ NO3-1
◦ 2 positives and one negativewhat is needed to balance the charges?
◦ Another negative or (NO3-1)2
Mg2+(NO3-1)2 - we need another whole anion so use brackets
Write out symbols from table
Put brackets around ions with two
elements (two capitals) eg SO2-4
Count the number of positives and negatives
Balance charges by multiplying ion
Check it balances
Rewrite without charges
Formulas show how many atoms of each type are in a compound
The bottom right hand number tells us how many of the atoms directly before it there are.
◦ H20 = 2 hydrogen atoms, one oxygen atom
We don’t write 1 in as we are lazy!
The number directly outside a bracket is a multiplier of everything inside the bracket.
◦ Al(OH)3 = 1 Al, 3 O, 3 H
◦ (NH4)3PO4 = 3N, 12 (3x4) H , 1P, 4 O
To get the total number of atoms we work out how many of each atoms there are and then add them
◦ (NH4)3PO4 = 3N, 12 (3x4) H , 1P, 4 O
◦ 3+12(3x4)+1+4 = 20 atoms
A big number in front means two of the whole compound – so work out how many of each atom there is, add them up and then multiply this by the big number at the front.
◦ 2(NH4)3PO4 = 3N, 12 (3x4) H , 1P, 4 O
◦ 3+12+1+4 = 20 atoms
◦ 20 x 2 = 40 atoms
Complete Scipad pages 20-27
Explain why the ions in sodium hydroxide combine to give the formula NaOH but the ions in beryllium hydroxide combine to give the formula Be(OH)2.
In your answer, you should:
compare the charges on the individual ions found in the compounds sodium hydroxide and beryllium hydroxide
explain why the ions combine in the ratios the way they do to form the compounds NaOH and Be(OH)2.
Comparison of charges on ions:
When these elements react, Na loses one electron and forms a +1 ion, while Be loses two electrons and forms a +2 ion in order to adopt the stable electron configuration. The hydroxide carries a charge of -1.
Explanation of formation of compounds:
An ionic compound is electrically neutral therefore all the positive charges must balance the negative charges.
Therefore it requires one OH-1 for each Na+ ion but two OH-1 ions for each Be2+ ion to form a neutral compound/ balance the charges.
Explain why the ions formed by sodium and oxygen both have the same electron arrangement. In your answer you should:• describe an ion• describe the atomic structures of a sodium ion and an oxide ion • state the charge on the sodium ion and the oxide ion• explain the charges on both ions in terms of electron arrangement and number of protons
Element X is between numbers 11 and 18 on the Periodic Table. An atom of element X forms an ion. This ion combines with the hydroxide ion to form a neutral compound, X(OH)3.
Determine what element X is and justify your answer.
In your answer you should:• consider the ratio of X ions to hydroxide ions • use the formula X(OH)3 to determine the charge of the X ion • explain how you would use the Periodic Table in your Resource Booklet to find out which group element X is in • name element X.
Write word equations for chemical reactions
Balance chemical equations
Reactant Product
There has to be the same number and type of each atom on both sides of the arrow –this is how you check you have balanced the equation correctly!
There are three types of equations
◦ Word equations (don’t need atoms balanced)◦ Symbol equations◦ Ionic equations (not need for level 1)
Step 1: Write out word equation
Magnesium + oxygen Magnesium oxide
Step 2: Write out symbol formula
Mg + O2 MgO
Step 3: Count atoms of each kind on each side
1 Mg 2 O 1 Mg 1O
Step 4: Identify the atoms with different numbers
2 oxygen atoms on left one on right
Step 5: Increase atoms by putting number:
in front of compound (2H2O) – makes 4 H & 2 O
after an ion (Mg2) – makes 2 Mg
brackets and a subscript around polyatomic ions (SO4)2 –makes 2 S & 8 O
Do hydrogen then oxygen atoms first
Mg + O2 2MgO
Step 6: Count atoms of each kind on each side –
they will have changed as a result of step 5!!!!
1 Mg 2 O 2 Mg 2O
Step 7: Identify the atoms with different numbers
1 Mg on left & 2 on right
Step 8: Increase atoms numbers
2Mg + O2 2MgO
Step 1: Write out word equation
Sodium + Water Sodium Hydroxide + Hydrogen
Step 2: Write out symbol formula
Na + H2O NaOH + H2
Step 3: Count atoms of each kind on each side
1 Na, 2 H, 1 O 1 Na, 1 O, 3 H
Step 4: Identify the atoms with different numbers
2 H 3 H
Step 5: Increase atoms by putting number:
Na + 2H2O 2NaOH + H2
Step 9: Count atoms of each kind on each side
1 Na 4H 2 O 2 Na 2 O 4H
Step 10: Identify the atoms with different numbers
1 Na on left and 2 on right
Step 11: Increase atoms numbers
2Na + 2H2O 2NaOH + H2
Step 12: Count atoms of each kind on each side
2 Na 4H 2 O 2 Na 2 O 4H
Same type of atoms and same number of atoms on both sides – DONE!
Nobody said it’d be easy but it does get easier, and remember practice makes perfect!
http://misterguch.brinkster.net/eqnbalance.html
http://www.files.chem.vt.edu/RVGS/ACT/notes/scripts/bal_eq1.html
http://www.sciencegeek.net/Chemistry/taters/EquationBalancing.htm
Complete Sci pad pages 28-31
Complete Scipad pages 8-9, 32-35
Complete purple book pages:
Complete worksheets:
In order for a reaction to occur particles need to collide
Particles need to collide with enough force to break bonds and form new ones
The more successful collisions the faster a reaction occurs
Complete Rates of Reaction Experiments
More successful collisions can be caused by:
◦ Increasing the temperature (particles move faster so collide more)
◦ Increasing the concentration (more particles to collide)
◦ Increasing surface area (small particles have greater surfaces for collisions to occur)
◦ Use a catalyst (holds chemicals so collisions can occur, lowers activation energy needed to break bonds)
◦ Increase pressure (particles are closer together therefore collide more often)
Increasing collisions increases rate of reaction!
What is the difference between particle theory and collision theory
Complete Rates of Reactions Experiments
Complete worksheets
Complete scipad pages 37-39, 48-53
Complete pages 40-47 (all the equipment you need is up the front)
http://www.kscience.co.uk/animations/collision.htm
Particle theory – all matter is made up of particles which are in constant motion
Collision theory – particles need to collide with enough force and energy to break bonds and form new ones
More particles more collisions faster rate of reaction
More movement more collisions faster rate of reaction
Calcium carbonate (marble chips) and hydrochloric acid react together in a conical flask.The word equation for this reaction is:
calcium carbonate + hydrochloric acid → calcium chloride + water + carbon dioxide gas
(a) Describe an observation you would make when this reaction occurs.
(b) Explain why the mass decreases with time.
When more concentrated hydrochloric acid is used, the reaction is faster.
© Explain the difference in the rate of reaction.
In your answer you should refer to: • particles • collisions • reaction rate.
Fizzing / bubbling occurs, marble chips decrease in size, heat is produced.
Why mass decreasesThe marble chips decreases as one of the products is CO2 gas. This gas escapes and so the mass of the flask and contents is reduced.
What’s happeningAs the reactant particles collide, they form product particles. As the reaction proceeds, there are fewer and fewer reactant particles left to collide and so the rate of reaction becomes slower.
At the start (section X) of the reaction, more product particles are being formed, then more gas is being formed, therefore more gas escapes at first and so the mass of the flask and contents decreases more rapidly. At X, the rate of reaction is fast but decreasing with time.
In section Y there are now fewer (less) reactants and so there are fewer collisions per second (unit time) and so less product is formed, ie less gas being released, so the mass does not decrease as rapidly. At Y, the rate of reaction is slow and slowing.
In section Z the reaction has stopped, as one of the reactants (marble chips or HCl) has run out, so there are no particles left to react.
When more concentrated acid is used, there are more acid particles in the same volume of the acid. Because of this, there are more particles to collide with the calcium carbonate. Because there are more to collide, the rate of reaction is faster.
Explains why the reaction is faster, by linking the idea that there are more acid particles in the same unit volume available for collisions, and hence there will be more collisions, causing the faster reaction rate
http://lgfl.skoool.co.uk/content/keystage4/chemistry/pc/lessons/uk_ks4_rates_of_reaction/h-frame-ns6.htm
Define the terms acid, base and alkali
Name and write the formula of three common laboratory acids
Classify acids and alkalis as chemicals with distinct properties and uses.
Substance Acid (red/orange)
Base (purple/blue)
Neutral(green)
Taste sour pH less than 7
Turn litmus red Contain hydrogen ion H+
Conduct electricity
Acid rain (oxides of sulphur and nitrogen from factories dissolve in water to form acid rain)
citric juice, stomach acid (HCl), vinegar, battery acid
Acid reactions:◦ Acid + base salt + water◦ Acid + metal salt + hydrogen gas◦ Acid + carbonate salt + water + carbon dioxide
Taste bitter, Feel slippery pH greater than 7 Turn litmus blue Alkali is a base that is soluble in water Metal oxides and metal hydroxides Most contain OH- ion, hydroxide ion Conduct electricity Soaps, oven cleaners (NaOH) Antacids (Mg(OH)2) – neutralise stomach acids Floor cleaners, bleach (ammonium hydroxide) Calcium hydroxide is limewater Calcium hydrogen carbonate – limestone caves Used to neutralise acids:◦ Neutralisation ◦ HCl + NaOH NaCl + H2O = pH 7◦ Acid + Base salt + water
Common Name Chemical Name
Formula Acid Base
Vinegar
Lemon juice
Grape juice
Soda Water
Antacids
Floor Cleaner
Battery Acid
Stomach Acid
Nitric Acid
Hydrochloric Acid
Magnesium oxide
Common Name Chemical Name Formula Acid Base
Vinegar Acetic Acid C2H4O2
Lemon juice Citric Acid C6H8O7
Grape juice Tartaric Acid C4H6O6
Soda Water Carbonic Acid H2CO3
Antacids Magnesium Hydroxide MgOH
Floor Cleaner Ammonium Hydroxide NH4OH
Battery Acid Sulphuric Acid H2SO4
Stomach Acid Hydrochloric Acid HCl
Nitric Acid Nitric Acid HNO3
Hydrochloric Acid Hydrochloric Acid HCl
Magnesium oxide Magnesium oxide MgO
Complete Scipad pages 58-59 What is an Acid, What is a Base
List three common household acids and their formulas
List three common household bases and their formulas
Use the pH scale to compare the acidity and alkalinity of different solutions
We use a pH scale to tell us how acidic, basic or neutral a substance is.
Acids have a pH range from 1-6
Alkalis or bases have a pH range from 8-14
Neutral substances have a pH of 7
Strong acids contain more free H+ ions
Strong bases contain more free OH- ions
Most naturally occurring substances are weak eg. Citric acid in citrus fruit
Complete Scipad Investigations pages 61-62 Testing pH and Making Indicators
Complete Scipad page 63
Name and write the formula for various metal oxides, metal hydroxides, metal carbonates and hydrogen carbonate
Metal oxides contain oxide ion O2-
Rust Iron oxide FeO, Zinc oxide (sunscreen) ZnO
Basic
Acid + Metal Oxide Metal Salt + Water
Metal Hydroxide Contain hydroxide ion OH-
Antacids Magnesium hydroxide MgOH
Form when metal or metal oxide reacts with water
Acid + Metal Hydroxide Metal Salt + Water
Metal Carbonates Contain the carbonate ion CO3
-
Calcium carbonate CaCO3- marble chips
Release carbon dioxide when react with acids Acid + Metal Carbonate Metal Salt + Water
+ Carbon Dioxide
Metal Hydrogen Carbonates Contain hydrogen carbonate ion HCO3
-
Neutralise acids Produce carbon dioxide when reacted with acids Calcium hydrogen carbonate CaHCO3
Acid + Metal Hydrogen Carbonate Metal Salt + Water + Carbon Dioxide
Name Metal Type Formulae
Copper oxide
CuCO3
Lithium hydroxide
FeO
Zinc carbonate
MgOH
Calcium hydrogen carbonate
Describe neutralisation reactions
Identify the products of neutralisation reactions
When we add base to an acid, a chemical reaction takes place.
The acid and base are used up in the reaction.
We say they are neutralised. They make a salt and water.
When a substance has been neutralised or is neutral it has a pH of around 7.
Acid + Base Salt + Water
Aim: To neutralise an acid using a base.
Method:
Step 1: Add four drops of sodium hydroxide to a test tube.
Step 2: Add one drop of universal indicator to the test tube and shake.
Step 3: Stop when the solution is green, if the solution turns red or orange add a very small drop of NaOHuntil the liquid turns green.
Complete Scipad practical page 64 Neutralisation
Complete scipad page 65
What causes indigestion?
-to much acid in the oesophagus
What do we need to add to neutralize that acid?
- Base! – Antacid, quickeze, mylanta, gavisconetc
Iron Magnesium Zinc Copper Lead
HydrochloricAcid
SulphuricAcid
Zinc SulphateZnSO4 No
Reaction
NitricAcid
Salts are named after the acids from which they are formed.• Hydrochloric acid forms chloride salts• Sulphuric acid forms sulphate salts• Nitric acid forms nitrate salts
http://lgfl.skoool.co.uk/content/keystage4/chemistry/pc/lessons/uk_ks4_acids_alkalis_salts/h-frame-ns6.htm
Complete pages 93, 94, 95
A student puts 5 mL of dilute hydrochloric acid into a boiling tube and adds five drops of universal indicator to the solution. The student then takes a solution of sodium hydroxide of the same concentration as the acid and adds it one drop at a time to the acid until the colour stops changing.
Describe the colour of the universal indicator solution:
◦ in the hydrochloric acid before any sodium hydroxide was added.
◦ when the sodium hydroxide was added and the colour of the solution stopped changing.
As the sodium hydroxide is added several colour changes occur.
Explain how the colour changes relate to pH AND what ions are present in the solution colour changes.
Description of colour changes:
red / pink to start with
blue / purple / violet at end.Explanation of colour changes:
At the beginning the red indicated a low pH due to excess H+ ions in the solution.
As the NaOH was added, a yellow / green colour indicates a pH of around 7, due to the OH- ions combining with the H+ ions to form a neutral solution.
As more NaOH is added the blue / purple indicated a pH of 11 plus, due to excess OH- ions in the solution.Identification of reaction type:
Acid-base (or acid-carbonate) neutralisation (the carbonate ions react with the H+
ions of the acidic solution and neutralise the solution).
Description of observations:
Bubbling in the solution / fizzing / effervescence / frothing / foaming Ca2CO3
disappears.
Linking observations to products:
The products are CO2, H2O and a salt. The CO2 gas causes the bubbles / fizzing / etc.
Writing a word equation:
Nitric acid + sodium carbonate sodium nitrate + water + carbon dioxide
Writing a symbol equation:
2HNO3 + Na2CO3 2NaNO3 + H2O + CO2
A student put 10 ml of dilute nitric acid in a boiling tube with five drops of universal indicator. Sodium hydroxide of the same concentration was then added. The following observations were recorded.
Discuss the reaction occurring as sodium hydroxide is added to the nitric acid.
In your answer you should:
• explain the relationship between the colours observed and the pH of the solution
• explain which ions cause the different colours of the solution
• write a word equation for the reaction AND a balanced symbol equation for the reaction.
Write word and symbol equations for a range of reactions involving acids and bases
Describe some everyday uses of acids, alkalis and neutralisation
Acid + Base Salt + Water
Hydrochloric acid + sodium hydroxide
sodium chloride + water
Test to see if reaction is complete by using indicator – solution should turn
Green
Complete scipad pages 66-68 Writing chemical equations
Complete Scipad practical Making Salts, page 69
Acid + Carbonate
Salt + Water + Carbon dioxide
Sulphuric Acid + Copper Carbonate
Copper sulphate + water + Carbon dioxide
We test for Carbon dioxide by bubbling the gas into lime water which turns
milky
Limewater (calcium hydroxide) reacts with carbon dioxide to produce a precipitate of calcium carbonate:
Ca(OH)2 (aq) + CO2 (g) → CaCO3 (s) + H2O (l)
Limewater + carbon dioxide calcium carbonate + water
If excess CO2 is added, the following reaction takes place:
CaCO3 + H2O + CO2 --> Ca(HCO3)2 (colourless)
Calcium Carbonate + water + carbon dioxide calcium bicarbonate
Complete Scipad practical page 70 Carbonates and Acids
Complete Scipad page 71-73
Acid + Metal Salt + Hydrogen Gas
Nitric Acid + magnesium
magnesium nitrate + hydrogen gas
We test for hydrogen gas by doing the
POP test
Acid + Base Salt + Water
Acid + Carbonate
Salt + Water + Carbon dioxide
Acid + Metal Salt + Hydrogen Gas
A student wanted to make the salt, magnesium chloride.
Discuss how the student would make magnesium chloride salt from hydrochloric acid and magnesium oxide.
In your answer you should:• state what type of reaction occurs• write a word equation AND a balanced symbol equation for the reaction between hydrochloric acid and magnesium oxide• explain how you would make magnesium chloride in a school lab from hydrochloric acid and solid magnesium oxide (this can be done by drawing labelled diagrams).
Type of reactionAcid-Base reaction or neutralisation.
Word Equationhydrochloric acid + magnesium oxide → magnesium chloride + water.
Balanced Equation2HCl + MgO → MgCl2 + H2O
How to make itAdd magnesium oxide to hydrochloric acid in a beaker. Heat slightly and pour this into an evaporating dish and leave somewhere warm (e.g. window sill) for a few days or heat over Bunsen to speed up the reaction, so that the water can evaporate, leaving magnesium chloride salt. Safe lab procedure would include dealing appropriately with chemicals such as HCl or the wearing of safety glasses
Complete Scipad pages 74-79
Brainstorm connecting words
Read the question and answer on the sheet,◦ highlight the connecting terms, ◦ use the marking schedule to mark it.
Swap and complete one more question
Complete questions on worksheet ◦ Use connecting terms!
Complete Scipad practice NCEA exam under exam conditions pages 80-85, mark it!!
Atoms and ions◦ Structure of an atom, number of protons, neutrons,
elections, electron configuration◦ Isotopes◦ Ion formation ◦ Ionic compounds
Rates of reactions◦ Particle theory◦ Factors affecting rate◦ Observations and tests for gases
Acids reactions◦ Properties of acids and bases◦ Common acid equations◦ pH, indicators and neutralisation◦ Word equations and balanced equations
