1.4_Elements_AS90933

=1.4 AS 90933 Demonstrate understanding of aspects of selected elements (4 credits) =

− trend across a period (position of metals and non-metals).

 * [[image:l1elementsbonding.jpg width="334" height="208" link="@file:chemicalbonds.swf"]] || [[image:l1elementsgroup1.jpg width="255" height="211" link="@file:group1.swf"]] || [[image:l1elementsbrainaicgroup1.jpg width="364" height="212" link="@file:Brainiac group1.wmv"]] ||


 * [[image:l1elementsgroup7.jpg width="264" height="213" link="@file:chemicalminds/group7.swf"]] || [[image:l1elementsferocious.jpg width="344" height="209" link="@file:chemicalminds/Ferociouselements.wmv"]] || [[image:l1elementsgroup8.jpg width="256" height="201" link="@file:group8.swf"]] ||

(b) Draw the electron arrangement for the magnesium and chloride ions
==== (c) Explain how magnesium and chlorine atoms react to form ions using the electron arrangements you have drawn above. Relate your answers to the positions of the atoms on the periodic table of elements. ====

− alloys.
====Physical properties may include – melting and boiling points (state), colour, lustre, hardness, ductility and malleability, electrical and thermal conductivity, density. ==== ====Chemical properties may include reaction with oxygen, water and acids (HCl, H2SO4). ====

NCEA PAST EXAM QUESTIONS on uses of metals
 
 * [[image:structuremetals.jpg width="374" height="206" link="@file:metalstructure.swf"]] || [[image:virtualtour.jpg link="@http://www.oresomeresources.com/public_html/media/flash/interactives/metals_matter/metals_matter/index.html"]] ||

You may refer to the activity series in the Resource Booklet.
====Although copper is widely used throughout households for electrical wiring, aluminium is the metal used for long-distance power lines. Evaluate the advantages and disadvantages of using copper and aluminium in these roles. ====

Refer to BOTH physical and chemical properties in your answer.


a justification as to why silver is preferable to iron for body jewellery.
==== One of the most common uses of aluminium is packaging, including soft drink cans and aluminium foil. Discuss why aluminium is used to package food and drinks despite the fact that aluminium is a reactive metal, found quite high up on the activity series (shown in your Resource Booklet). Include in your answer: ====

why aluminium can be used in packaging food and drink when the metal is quite reactive.
==== Sodium is not a metal that is usually used to make everyday objects, whereas aluminium is. For example, aluminium is used to make many objects from aeroplanes to soft drink cans. Discuss reasons for the difference in the uses of sodium and aluminium. Refer to the chemical **and** physical properties of **both** sodium and aluminium in your answer. ==== ====You have been asked to design a long-lasting metal roofing system for a house. The metals that are available are copper and iron. Discuss the suitability of each metal for a roofing system. Refer to relevant physical and chemical properties of each metal in your answer. ==== ====Gold is a metal that is often used to make jewellery. Name two properties of gold that make it suitable for this use. Explain why the two properties you named in part (a) help make gold suitable for making jewellery. ==== ====State the physical or chemical properties of aluminium that make the metal suitable for each of the uses given in the table below. Write a DIFFERENT PROPERTY in each cell of the table. Each property must relate to the given use. ====  <span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif;">

<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">NCEA PAST EXAM QUESTIONS on Alloys
<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;"> ==== Aluminium alloys are used to make planes and helicopters. Explain the advantages of using an aluminium alloy, rather than pure aluminium, for this purpose. In your answer, you will need to explain how the structure and properties of an alloy differ from those of a pure metal. You may use a labelled diagram to illustrate your answer. ====
 * [[image:l1elementalloy.jpg width="231" height="209" link="@http://www.dynamicscience.com.au/tester/solutions1/war/metallurgy/metalsalloy.htm"]] || [[image:l1elementalloy3.jpg width="221" height="223" link="@http://www.glencoe.com/sites/common_assets/science/virtual_labs/PS14/PS_14_layout3.swf"]] || [[image:l1elementalloy2.jpg width="214" height="140" link="@http://resources.schoolscience.co.uk/Corus/16plus/steelch2pg5.html"]] ||

Each of the metals used to make surgical steel, shown in the table below, contributes to its final properties.
==== Evaluate why each of the metals listed in the table above is used to make surgical steel alloy suitable for use as body piercing jewellery. In your answer link ONE physical and ONE chemical property of **each** of these metals to its final use as body piercing jewellery. ====

<span style="color: #221e1f; font-family: Arial,Helvetica,sans-serif;">1. Sterling silver is an alloy made of 92.5% silver and 7.5% copper.
<span style="color: #221e1f; font-family: 'Times New Roman',serif; font-size: 16px;"> ====<span style="font-family: Arial,Helvetica,sans-serif;">(i) Describe ONE physical and ONE chemical property of pure silver that make it useful in the production of jewellery and other precious objects. You may refer to the activity series provided in the resource booklet. ==== ====<span style="font-family: Arial,Helvetica,sans-serif;">(ii) Analyse the advantages and disadvantages of using sterling silver instead of pure silver in the production of jewellery and other precious objects. In your answer you should include physical and chemical properties of each of the metals used to make sterling silver. You may refer to the activity series provided in the resource booklet. ====

(b) Explain why an alloy is **harder** than a metal.In your answer refer to the diagrams below.
<span style="font-family: Arial,Helvetica,sans-serif; line-height: 0px; overflow: hidden;"> ====Alloys often have properties that are different from the properties of the metals they contain. This makes alloys more useful than pure metals alone. For example, an alloy may be harder than the metals from which it is made.(a) Explain why an alloy may be harder than the metals from which it is made. You may draw a labelled diagram in the box provided to support your answer. The table below gives some information about TWO alloys of gold.====

<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">NCEA PAST EXAM QUESTIONS on Reactivity of metals with oxygen
<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;"> <span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">

<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">NCEA PAST EXAM QUESTIONS on Reactivity of metals with water
<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;"> <span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">

Discuss the reactivities of calcium and copper metals. In your answer, you should:

 * ====identify the chemical products formed in any reactions====
 * ====link the chemical products formed to the observations given in the table====
 * ====write balanced equations for the reactions that occur====
 * ====fully explain why calcium is placed before copper on the Activity Series (refer to the resource booklet).====

<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">NCEA PAST EXAM QUESTIONS on Reactivity of metals with acids
<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;"> <span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;">[[image:NCEA2011.jpg]]
====<span style="font-family: Arial,Helvetica,sans-serif;">Write both the observations and balanced equations for the reactions of sulfuric acid, H2SO4, with a cleaned piece of lead metal and with a cleaned piece of zinc metal. ====

<span style="font-family: Arial,Helvetica,sans-serif;">You may refer to the Activity series in the Resource Booklet.
<span style="font-family: Arial,Helvetica,sans-serif;"> ====<span style="font-family: Arial,Helvetica,sans-serif;">An investigation was carried out where identically sized pieces of the metals magnesium, zinc, and copper were placed in separate test tubes. The same volume and concentration of hydrochloric acid was added to each test tube. ====

<span style="font-family: Arial,Helvetica,sans-serif;">Copper and hydrochloric acid
====<span style="font-family: Arial,Helvetica,sans-serif;">(b) Discuss the reactions that may occur with reference to the reactivity of the three metals. Include the balanced equations, where appropriate. ====

<span style="font-family: Arial,Helvetica,sans-serif;">Refer to the activity series provided in the Resource Booklet.
<span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif; line-height: 0px; overflow: hidden;">

<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">− selected compounds include – sulfuric acid, ammonia, sulfur dioxide.
====<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">Physical properties may include – melting and boiling points (state), colour, lustre, hardness, ductility and malleability, electrical and thermal conductivity, density. ====

<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">NCEA PAST EXAM QUESTIONS on sulfur, sulfur dioxide and sulfuric acid
<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;"> <span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;">Explain why the sulfuric acid solution conducts electricity so well. Include a balanced equation in your answer
<span style="font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;">• any relevant balanced equations.
<span style="font-family: Arial,Helvetica,sans-serif;">

<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">NCEA PAST EXAM QUESTIONS on aqueous chlorine
<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;"> ====<span style="font-family: Arial,Helvetica,sans-serif;">(a) Chlorine water is formed by adding chlorine gas to water. Some of the chlorine dissolves in water and some reacts with water. Explain what happens to a piece of blue litmus paper when it is used to test the chlorine water. In your answer you should: ====
 * [[image:l1ellementsCltest.jpg width="301" height="222" link="@file:l1elementsCltest.mp4"]] || [[image:l1elementsClvideo.jpg width="293" height="213" link="@file:l1elementsClvideo.mp4"]] ||

<span style="font-family: Arial,Helvetica,sans-serif;">• write a balanced symbol equation for the reaction of chlorine gas with water
====<span style="font-family: Arial,Helvetica,sans-serif;">(b) In hospitals, chlorine-based solutions are used in cleaning and disinfecting to help protect patients from infection. Justify why chlorine-based solutions are used in hospitals by explaining how the chemical properties of chlorine-based solutions make them suitable for cleaning and disinfecting. ====

(c) Explain why chlorine needs to be added to pool water at regular intervals.


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