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NCEA Level 1Science Directions Workbook

Acids and Bases1.5 (AS 90944) Demonstrate Understanding of Aspects of

Anne Wignall, Terry Wales, Wendy Robinson and Janet Dixon

NDS-WB-2012_Acids and Bases.indd 1 5/09/12 1:17 PM

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ContentsPage/Section Objectives Workbook activities Quizzes* Revision activities*2 A Matter

Define the terms element, compound and mixture in terms of the particles they contain. Write a word equation for a given reaction. Recognise what is required for a balanced equation.

A 1 Matter mattersA 2 Modeling matter (prac)A 3 Equation practice

A 1 Matter factsA 2 Balanced equations

3A 1 Matter facts3A 2a Balanced or not balanced? 3A 2b Assembling balanced equations

8 B Inside atoms

Recall the structure of atoms in terms of a central nucleus containing protons and neutrons and surrounded by electrons.Recall that almost all the mass of an atom is concentrated in the nucleus. Define the terms atomic number, mass number and isotope.

B 1 Atom wordsB 2 How chemists changed the NZ wine industry

B 1 Atomic structure key factsB 2 Inside an atomB 3 Counting atomic particles

3B 1 Atomic structure key facts 3B 2a Atomic structure 3B 2b Inside an atom 3B 3a Atomic particles 1 3B 3b Atomic particles 2 3B 3c Atomic particles 3

12 C Atoms and ions

Explain why atoms are neutral, define the term ion and explain why ions are charged particles. Relate the atomic number of an element to its position on the periodic table. Predict the electron arrangement of an atom from its position on the periodic table for any of the first 20 elements.

C 1 Electron structure of the elementsC 2 The internal structure of atoms (prac)

C 1 Atoms and ionsC 2 The periodic table and electron arrangements

3C 1 What charge? 3C 2a The periodic table 3C 2b Outer-shell electrons and ions 3C 2c Atoms and elements flipcards

18 D Forming ions

Use the electron structure of an atom to predict the charge on the ion it will form (if any).

D 1 Atoms and ions D 1 Electron arrangements and ions

3D 1 Ions and the periodic table

21 E Ionic formulas

Explain in simple terms what an ionic bond is. Name ions and ionic compounds from their formulas. Explain why ions combine in the ratios they do in ionic formulas. Write the formula for a given ionic compound given a table of ions. Count atoms in a given chemical formula.

E 1 Reading chemical formulas E 2 Ionic jigsawsE 3 More formulasE 4 Parlez vous chemistry?E 5 Mainly minerals

E 1a Naming ionsE 1b Naming ionic compounds 1E 1c Naming ionic compounds 2E 2 Counting atomsE 3a Writing ionic formula 1E 3b Writing ionic formula 2E 4 Matching formulae for common substances

3E 1a Naming ions 1 3E 1b Naming ions 2 3E 1c Naming ions 3 3E 1d Matching chemical formulae 1 3E 1e Matching chemical formulae 2 3E 1f Chemical formula 3 3E 1g Chemical formulae 4 3E 2 Counting atoms 3E 3a Which formula is correct? 3E 3b Writing formulae 3E 4 Common names

29 F Acids and bases

Recall the characteristic properties of acids and bases including concentration of H+ and/or OH–. Recall the names and formulas for hydrochloric acid, nitric acid and sulfuric acid. Recall the colour changes of litmus or universal indicator in acidic, basic and neutral solutions.Use the pH scale to indicate degree of acidity or basicity. State that food acids release fewer hydrogen ions in solution than laboratory acids, and relate this to the pH of the solutions formed when different acids dissolve in water.State that when hydroxides dissolve in water they release hydroxide ions which make the solution basic.Identify metal oxides, carbonates and hydrogen carbonates as substances that react with water to form basic solutions.Explain why some metal oxides form solutions of high pH and others form solutions of only moderate pH.

F 1 Testing pH (prac)F 2 Acid, base, or neutral?F 3 Experimental design: soil testing

F 1 Acids or bases?F 2 Laboratory indicatorsF 3 Indicators and pHF 4 Nature of laboratory solutions

3F 1a Properties of acids and bases (group) 3F 1b Classifying substances as acid or base 3F 1c Acid or base? 3F 2a Laboratory indicators 3F 2b Universal indicator and pH3F 3a The colours of universal indicator 3F 3b Order pH 3F 3c Indicator and pH facts3F 4a Strong and weak acids and bases3F 4b Nature of laboratory solutions


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Page/Section Objectives Workbook activities Quizzes* Revision activities*41 G Neutralisation

Discuss changes in pH or indicator colour during neutralisation reactions.Name the salts formed by hydrochloric, sulfuric and nitric acids.Write word and balanced formula equations for reactions between acids and metal hydroxides, oxides, carbonates or hydrogen carbonates.Describe the visible effect of adding acid to a carbonate or hydrogen carbonate.Describe the limewater test for carbon dioxide and write balanced equations for the two reactions that occur during this test. Complete word or formula equations for making specific salts.

G 1 Neutralising an acid (prac)G 2 Making a salt (prac)G 3 Acid on a carbonate (prac)G 4 Carbon dioxideG 5 A balanced lifeG 6 Reaction time

G 1a Acids and bases key factsG 1b Complete word equations by adding acidsG 2a Hydroxide key factsG 2b Oxide equationsG 2c Oxide & hydroxide equations G 3 CarbonatesG 4a Complete word equations – carbonatesG 4b Balanced equations for carbonatesG 5 Neutralisation equations

3G 1a Salts from acids 3G 1b Salts from acids 3G 1c Classifying compounds 3G 1d Acids and bases facts 3G 1d Acid-base memory 3G 1e Name compounds 3G 2a Complete acid-base word equations 3G 2b Balancing equations 1 3G 3 Carbonate facts 3G 4 Acids and carbonates equations 3G 5a Missing substance 3G 5b Completing mixed word equations 3G 5c Completing word equations – acid reactions 3G 5d Balancing equations 2 3G 6 Acid-base flipcards

55 H Applications

Apply an understanding of pH and neutralisation reactions to situations in everyday life.

H 1 Soil pH and acid rainH 2 Household cleanersH 3 IndigestionH 4 bLIMEy!H 5 Swimming pool chemistry

H 1 Soil pH and acid rain 3H 1 Soil pH and acid rain

60 I Rates of reaction

Summarise the principles of particle theory.State that as the size of the pieces decreases, the total surface area increases. Describe what would be observed in a controlled investigation into how the size of the pieces affects reaction rate. Describe what would be observed in a controlled investigation into how concentration affects reaction rate. Describe what would be observed in a controlled investigation into how temperature affects reaction rate. Apply particle theory to explain the effect of temperature on reaction rate. Describe test tube observations of reaction rate with time.

I 1 The size of the pieces and reaction rate (prac)I 2 Experimental design: the size of the piecesI 3 Concentration and reaction rate (prac)I 4 Time for a quick one?I 5 Temperature and reaction rate (prac)I 6 Rates questions I 7 Disappearing malachiteI 8 A reaction study

I 1 Rates experimentsI 2a Particle theoryI 2b Rates of reactionI 3 Surface area experimentsI 4 Concentration experimentsI 5 Temperature experimentsI 6 Rates reasons

3I 1 Rates experiments3I 2a Principles of particle theory 3I 2b Defining particle theory 3I 3 Surface area3I 5 Temperature and concentration in reaction rates 3I 6b Rates reasons 3I 7a Chemistry crossword 3I 7b Chemistry revision flipcards

* On the Teacher Resource


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A MatterAll matter is either a pure substance or a mixture of pure substances.

Pure substances are either elements or compounds.

Elements are composed of only one kind of atom. All the elements are listed on the periodic table of elements and each one has its own chemical symbol.

Compounds are composed of different kinds of atoms that are chemically combined in specific ratios. A compound’s chemical formula shows the ratios of each kind of atom.

Mixtures may contain elements or compounds that are mixed together but not chemically combined.

Air contains the elements oxygen and nitrogen, and the compounds water and carbon dioxide.

Steel is an alloy made of iron with a small amount of carbon mixed in.

Iron is a solid element. Nitrogen is a gaseous element consisting of N2 molecules.

In sodium chloride there is one Na for every Cl: NaCl.

In methane there is one C for every four H atoms: CH4.


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Elements can be divided into metals, such as iron, copper and magnesium, and non-metals, such as carbon, sulfur and oxygen.

Compounds can be classed as ionic or covalent, according to the kinds of chemical bonds holding them together.

Ionic compounds form when electrons are transferred between atoms to form ions, which have positive or negative charges. Examples include NaCl and MgO.

Covalent compounds form when non-metal atoms share electrons. Examples include CO2 and H2O.

Element Compound Mixture

MatterPure substance A sample of an or a compound.

Mixture Two or more elements or compounds, mixed together but not combined.

Element Made of only one kind of .

Compound Two or more kinds of atom, combined.

Atom The smallest particle of an .

Ion An atom that has or lost electrons.

Put these substances into the correct groups:water air oxygen carbon dioxide saltmagnesium gold HCl H2 seawater chocolate cake iron steel copper sulfate


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Chemical reactions

In chemical reactions, the atoms in elements or compounds break apart, then combine in different ways to form new substances.

In a balanced chemical equation, the numbers of atoms of each kind must be equal on each side of the arrow.

All formula equations must be balanced.

If new substances are not formed, the process is a physical change and not a chemical reaction.

Chemical reactions

When chemical reactions occur, atoms are to form new substances.

Balanced equations

In a balanced chemical , the numbers of atoms of each type on each of the arrow must be .

2H2 + O2 2H2O

2H2 + O2 2H2O Balanced

H2 + O2 H2O Not balanced

H2 + O2 H2O Not balanced 2H2 + O2 2H2O Balanced


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A1 Matter matters 1 Complete the diagram below, using the words on the left.

Matter

S & C

Pure substancesSteel & brassNaCl & MgOCompoundsNon-metalsMixturesElementsCovalentAl & CaMetalsAlloysIonic

CO2 & H2O

2 Match the words below with their definitions.

metals ionic bond atom non-metals matter covalent periodic table ion molecule

a An atom or group of atoms that has gained or lost electrons.

b A bond formed between oppositely-charged particles.

c Elements that are shiny, conduct heat and electricity, and are malleable.

d Type of compound involving only non-metals.

e Formed when two or more non-metal atoms join.

f The smallest part of an element.

g Elements that are often gases or brittle solids.

h Anything that has mass and occupies space.

i A special chart showing all the elements.

Says who?


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A 2 Modelling matter Your teacher will give you at least two different colours of plasticine or play dough. Use different colours to represent different elements.

Part 1: Elements and compounds

1 Oxygen, O2, is a gaseous element composed of 2-atom molecules. Build six molecules of oxygen.

2 Use six atoms to build a model of carbon, a solid element, using a different colour from that used for oxygen.

3 Now use your models to illustrate what happens when carbon burns to make molecules of carbon dioxide, CO2. Draw pictures below to show what happens.

4 You may have done an experiment in Year 9 with iron and sulfur. First iron and sulfur are examined separately, then iron and sulfur powders are mixed together and separated again with a magnet. Finally, a mixture of iron and sulfur is heated to make the compound iron sulfide.

Build models to show what happens in this experiment, and draw pictures on the right to represent pure iron, pure sulfur, the mixture of iron and sulfur, and the compound iron sulfide.

Thinking about it (1)5 Use your answer to 4 to explain, on a particle level, the difference between a physical change and a

chemical change.

Part two: equations

In a mathematical equation, the totals on each side of the equals sign must be equal. In a chemical equation, the number and type of atoms on both sides of the arrow must be equal.

6 Make an arrow out of your plasticine or play dough.

7 Make models of hydrogen (H2), oxygen (O2), and water (H2O), and use them to build an equation showing what happens when hydrogen is burnt in oxygen to form water. (Hint, you will need more than one hydrogen molecule.)

8 Write a formula equation for the reaction you built in 7.

9 When methane (CH4) burns in oxygen, the products are carbon dioxide (CO2) and water (H2O). Build the equation for this reaction. Be sure to have the same number of each type of atom on each side of the arrow.


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10 Write a formula equation for the reaction you built in 9.

Thinking about it (2)11 What does the arrow mean in a chemical equation?

A 3 Equation practice1 Match the reactants with their products. One has been done for you.

Reactants Products

a zinc hydroxide + hydrochloric acid → sodium citrate + water + carbon dioxide 1

b copper oxide + sulfuric acid → zinc sulfate + hydrogen 2

c citric acid + sodium carbonate → lead chloride + water + carbon dioxide 3

d magnesium oxide + nitric acid → iron citrate + hydrogen 4

e sulfuric acid + zinc → aluminium chloride + water 5

f hydrochloric acid + lead carbonate → potassium sulfate + water 6

g magnesium + acetic acid → copper sulfate + water 7

h sulfuric acid + potassium hydroxide → magnesium nitrate + water 8

i iron + citric acid → 4 zinc chloride + water 9

j hydrochloric acid + aluminium oxide → magnesium acetate + hydrogen 10

2 Match the reactants with their products.

Reactants Products

a Pb(OH)2 + 2HCl → Mg(NO3)2 + 2H2O 1

b Ca + H2SO4 → CaCl2 + H2O + CO2 2

c 2HCl + CaCO3 → PbCl2 + 2H2O 3

d Mg(OH)2 + 2HNO3 → FeCl2 + H2 4

e 2HCl + Mg → ZnSO4 + H2O + CO2 5

f H2SO4 + 2NaOH → CaSO4 + H2 6

g Fe + 2HCl → Ca(NO3)2 + H2O 7

h 2HCl + CuCO3 → MgCl2 + H2 8

i H2SO4 + ZnCO3 → Na2SO4 + 2H2O 9

j CaO + 2HNO3 → CuCl2 + H2O + CO2 10


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B Inside atomsAtoms consist of a tiny nucleus containing positively-charged protons and neutral neutrons, surrounded by a cloud of negatively-charged electrons.

Electrons are almost 2000 times smaller than protons and neutrons, so almost all the mass of an atom is concentrated in its nucleus.

Atomic symbols

Scientists summarise the most important data about an atom by listing its atomic number and its mass number.

The atomic number is equal to the number of protons.

The mass number gives the total number of massive particles: the protons and neutrons.

This diagram shows that the electrons are found in shells.

Although there are only a few electrons, they move so fast they seem to occupy the whole volume of the atom.

This atom has: 5 protons 11 – 5 = 6 neutrons 5 electrons

Mass number

Atomic number

Protons Neutrons Electrons


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Inside atoms

Isotopes

The nucleus, in the centre of an atom, contains and neutrons, while the orbit the nucleus in .

The atomic number is the number of in an atom.

The mass number is the number of protons plus .

are atoms with the same number of protons but different numbers of neutrons.

Isotopes have the same atomic number but different numbers.

They have the same chemical properties because they have the same structure. However, because isotopes have slightly different some of their physical are different.

Particle Mass Charge Position

Proton 1 +1 Nucleus

Neutron 1 0 Nucleus

Electron 1 1836

-1 Shells


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B 1 Atom words1 Match the words below with their definitions.

atom mass number neutron nucleus isotopes proton atomic number electron

a A positively-charged particle.

b Place inside an atom where the mass is concentrated.

c Tells the total number of particles in the nucleus.

d A particle with charge but almost no mass.

e Neutral, subatomic particle.

f Equal to the number of protons in the atom.

g Particle whose volume is almost entirely empty space.

h Particles with the same atomic number but different mass numbers.

2 A group of students was trying to decide which of the words in the box below was the odd one out.

Electron Proton Neutron Nucleus

Complete these answers by giving a reason for each choice.

a Jason: Nucleus is the odd one out because...

b Ji-Hyun: Neutron is the odd one out because...

c Emily: Electron is the odd one out because...

3 Which of the particles X, Y and Z below:

614

714

715X Y Z

a have the same number of protons?

b have the same number of neutrons?

c are isotopes of the same element?

4 Use the periodic table at the back of your book to work out the correct symbols for elements X, Y and Z.

X = Y = Z =

Words?What words?

Where’s‘idiot’ whenyou want it?


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B 2 How chemists changed the NZ wine industryToday New Zealand earns about 1 billion dollars in wine exports each year, but New Zealand hasn’t always made good wine. In the 1970s, wine-makers would ‘stretch’ their grape juice by adding water and sugar, producing large volumes of cheap wine – about twice the volume that could be made from grape juice alone. Adding water was illegal, but government chemists couldn’t tell the difference between water from a grape and water from a tap or between alcohol made from grape sugar and that made from cane sugar. Chris Hendy, a Waikato University chemist, wanted to see whether isotope analysis on wine would work.

Carbon has two stable isotopes: 12C and 13C. Both isotopes undergo the same chemical reactions, but the rate of reaction in plants is slightly slower with the heavier isotope. The result is that in woody plants such as grapes, the ratio of 12C to 13C is slightly higher in the plant than it is in the air. In cane sugar, though, the ratios in the plant and in the air are the same (because the process of photosynthesis is different in cane sugar and other tropical grass-like plants). So Chris could use the 12C to 13C ratio in each wine sample to calculate the amount of cane sugar that had been added. There was also an isotopic difference between the water from grape juice and that from a tap. Oxygen has three stable isotopes and hydrogen has two. As the grapes ripen, the plant loses water through transpiration, and water molecules composed of the lighter isotopes evaporate more quickly than the heavier molecules. Thus by the end of the season the grape juice contains a higher proportion of these heavier isotopes than tap water.

With the help of some friendly wine-makers, Chris and his students developed analytical methods that meant they could accurately determine how much water and cane sugar had been added to any wine sample. Their results were published in Consumer in 1980 and by 1982 the watering of wine in New Zealand had completely stopped – and the price of wine doubled from $1 to $2 per bottle. Two years later, the government allowed the unrestricted importation of wine into New Zealand. When the local wine-makers couldn’t compete on price or quality, the government paid them to rip out their old, low-quality grape vines and plant better varieties such as Chardonnay, Sauvignon Blanc, Pinot Noir and Syrah. That’s when we started making good wine.

1 Oxygen has three stable isotopes, 16O, 17O and 18O. Complete the table on the right to show whether these isotopes are the same or different in the factors named.

2 Selling wine containing a large amount of water was illegal in New Zealand long before Chris started his analysis of wine. Explain why the watering of wine didn’t stop until 1982.

3 Wine X has a greater proportion of 13C than wine Y. Which one has more cane sugar added? Why?

One of Chris’s students, Alan Limmer, went on to start the Stonecroft winery in Hawke’s Bay.

Factor Same or different?Number of protons

Number of neutrons

Number of electrons in the neutral atomPhysical properties

Products in chemical reactionsRate of reaction in plants


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