1.5_AcidsBases_AS90944

==1.5 AS 90944 Demonstrate understanding of aspects of Acids and Bases (4 credits) ==

__ ATOMIC STRUCTURE __

 * [[image:l1sciatomsspace.jpg width="245" height="199" link="@file:atomsspacebetween.mov"]] || [[image:l1scireviewatoms.jpg width="308" height="120" link="@file:reviewatomsions.swf"]] || [[image:l1sciPTshells.jpg width="325" height="164" link="@file:PT of shells.swf"]] ||


 * [[image:l1sciflask.jpg width="345" height="102" link="@file:bondingflask.swf"]] || [[image:l1sciseesaw.jpg width="346" height="181" link="@file:seesaw balance.swf"]] || [[image:l1sciionsummary.jpg width="234" height="170" link="@http://www.pbslearningmedia.org/asset/lsps07_int_ionicbonding/"]] ||

N CEA PAST EXAM QUESTIONS on Atomic structure


(c) Sodium burns in oxygen gas, O2, to form sodium oxide, Na2O.
====(i) Explain how the Na and O atoms form Na+ and O2– ions, in terms of their groups in the periodic table, electron arrangement, AND number of protons. ====

the charge on each ion. Include an explanation of the type of bonding between the Na+ and O2– ions.


(iii) Zinc nitrate
====(b) Complete the table below for the ions formed by magnesium, aluminium, and oxygen. Use the periodic table in your Resource Booklet to help you. ==== ====(c) The formula for magnesium oxide is MgO. The formula for aluminium oxide is Al2O3. Explain why the two formulae are different. In your answer: ====

• explain the charges on both ions in terms of electron arrangement and number of protons.
====**b)** 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:====

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.====

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.====

**d)** Explain why Li is a **neutral** atom. In your answer, you should fully describe its atomic structure and state the electron configuration.
====Aluminium reacts with oxygen to form aluminium oxide. The formula of aluminium oxide contains two aluminium ions and three oxide ions. Discuss why the formula has two aluminium ions and three oxide ions. In your answer you should: ====

**b) i)** Using similar symbols, draw a diagram that shows a sodium atom
====**ii)** Discuss the similarities and differences between a sodium atom and a sodium ion. You should consider the number of protons, electrons and neutrons, and the charge of each particle. ====

**ii)** How many atoms are there in 2Al(OH)3?


**e)** Name these compounds: CuCl2 Zn(OH)2 KF
====**f)** Refer to the positions of oxygen and fluorine in the Periodic Table provided in the Resource Booklet. Comparing oxygen and fluorine, discuss how the electron arrangement, the atoms’ positions in the Periodic Table and the charges on their ions are related.====

**d) i)** How many atoms of oxygen are there in the formula Mg(HCO3)2? What is the total number of atoms in the formula?
**ii)** Using the Table of Ions provided in your Resource Booklet, write formulae for: calcium oxide, copper hydroxide, sodium carbonate **iii)** Name each of these compounds: MgO, Na 2 S, Ca(NO 3 ) 2 **e)** The doctor told Miriam she was tired and pale because she was low in iron. The iron tablets Miriam was given to take did not look like the iron nails they used in woodwork. Discuss how the **chemical** differences between the iron in the tablets and the iron in the nails are related to their uses.



__PROPERTIES AND USES OF ACIDS AND BASES __

 * [[image:level1sciencepH.jpg width="282" height="208" link="@file:pH scale.swf"]] || [[image:level1sciencebase.jpg width="296" height="193" link="@http://www.bgfl.org/bgfl/custom/resources_ftp/client_ftp/ks3/science/acids/"]] ||


 * [[image:level1sciencephetacid.jpg width="304" height="207" link="@https://phet.colorado.edu/sims/html/acid-base-solutions/latest/acid-base-solutions_en.html"]] || <span class="wiki_link_ext">[[image:level1scimakingsalts.jpg width="317" height="203" link="@file:makingsalt.swf"]] || [[image:level1scienceskoolacidbase.jpg width="360" height="195" link="@http://www.skoool.ie/content/skoool_learning/junior/lessons/science/acids_alkalis_salts/flash/h-frame-ns6.htm"]] ||

<span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;"> NCEA PAST EXAM QUESTIONS on Properties and Uses of Acids and Bases
<span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;"> <span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;">

**1)** Write a word equation AND a balanced symbol equation for the reaction between calcium carbonate and hydrochloric acid.
====**2)** A student has three unlabelled beakers each containing a colourless liquid. One contains water, one contains a solution of baking soda (sodium hydrogen carbonate), and one contains white vinegar (a solution of ethanoic acid).==== ====To work out which liquid is which, the student put a drop from each beaker onto a piece of blue litmus paper and a piece of red litmus paper. She then added universal indicator to each beaker. The following results were obtained:====

• state the approximate pH from the colour of the universal indicator.
====<span style="font-family: Arial,Helvetica,sans-serif;">(c) Another student was given two beakers (Beaker 4 and Beaker 5) each containing different liquids. The liquid in Beaker 4 had a pH of 1. The liquid in Beaker 5 had a pH of 6. Discuss which liquid is more acidic and how you know this. In your answer you should: ====

<span style="font-family: Arial,Helvetica,sans-serif;">• use the pH to determine which liquid is more acidic
====<span style="font-family: Arial,Helvetica,sans-serif;">• compare the amount of hydrogen ions AND hydroxide ions in Beaker 4 (pH 1) with the amount of hydrogen ions AND hydroxide ions in Beaker 5 (pH 6). ==== ====<span style="font-family: Arial,Helvetica,sans-serif;">**3)** A beaker contains sodium hydroxide solution and 5 drops of universal indicator. Sulfuric acid was added to the beaker until no more changes were observed. ====

<span style="font-family: Arial,Helvetica,sans-serif;">(a) Write a word equation AND a balanced symbol equation for the reaction between sulphuric acid and sodium hydroxide.
====<span style="font-family: Arial,Helvetica,sans-serif;">(b) Describe how the indicator colour changes as the sulfuric acid is added to the beaker, AND explain what this tells you about the changing pH of this solution. ====

<span style="font-family: Arial,Helvetica,sans-serif;">(c) Explain the relationship between the changing pH of the solution and the ions in the solution as the sulfuric acid is added to the beaker.
<span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;"> ==== Potassium hydroxide (KOH) was added to a solution of sulfuric acid containing universal indicator until no further change was observed. The experiment was repeated, but a piece of red litmus paper and a piece of blue litmus paper were each dipped into the solution after each 5 mL of potassium hydroxide was added. The results of the experiments are shown in the table below. ====

<span style="font-family: Arial,Helvetica,sans-serif;">(d) Explain why the mass of the beaker and contents would decrease over time.
====<span style="font-family: Arial,Helvetica,sans-serif;">1) Two beakers are shown below. Beaker one contains sulfuric acid solution and 5 drops of universal indicator. Beaker two contains pure water and 5 drops of universal indicator. Sodium hydroxide solution was added to both beakers until no more changes were observed. ==== **a)** Write a word equation AND a balanced symbol equation for the reaction between sulfuric acid and sodium hydroxide. **b)** What is the colour of universal indicator in each solution at the start? **c)** Describe the colour changes as sodium hydroxide solution is added to each beaker, AND explain what this tells you about the changing pH of each solution. **d)** Explain the relationship between the pH of the solutions and the ions in the solutions, as the sodium hydroxide is added to each of the beakers

**c)** Write a word equation AND a balanced symbol equation for the reaction between sodium carbonate and nitric acid.
====**1)** 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.====

• explain how you would make magnesium chloride in a school lab from hydrochloric acid and solid magnesium oxide (include labelled diagrams).
====A student puts 5mL 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.====

**ii)** 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.
====**b)** The student combines **equal** volumes of nitric acid solution and sodium carbonate solution. Both solutions have the **same concentration**. Discuss what happens in this reaction. In your answer, you should:====
 * ====name the type of reaction involved and the ions involved====
 * ====describe what the student would observe====
 * ====state the products of the reaction and link these to the observations made====
 * ====write a word equation for the reaction====
 * ====write a balanced symbol equation for the reaction.====

<span style="font-family: Arial,Helvetica,sans-serif;">**ii)** Write a balanced chemical equation for the reaction between potassium carbonate and hydrochloric acid.
====<span style="font-family: Arial,Helvetica,sans-serif;">**c)** In another experiment, sodium hydroxide solution is added slowly to the hydrochloric acid to which Universal Indicator solution has been added. ====

<span style="font-family: Arial,Helvetica,sans-serif;">**i)** Describe how the colour of the Universal Indicator solution changes as the sodium hydroxide solution is added.
====<span style="font-family: Arial,Helvetica,sans-serif;">**ii)** Discuss how the colour changes relate to the substances present in the solution. Use the substances from the key list: water, sodium chloride, sodium hydroxide, hydrochloric acid ====

<span style="font-family: Arial,Helvetica,sans-serif;">**c)** This reaction is described as a neutralisation reaction. Explain what is meant by the term neutralisation.
====<span style="font-family: Arial,Helvetica,sans-serif;">**1)** James carried out an investigation to see how many colours he could make with universal indicator. He started with 5 mL of dilute hydrochloric acid in a boiling tube and added 5 drops of universal indicator. The solution turned red. James then added dilute sodium hydroxide to the boiling tube, a drop at a time, until the solution turned purple. ==== ====<span style="font-family: Arial,Helvetica,sans-serif;"> **i)** James obtained three more colours as he added the sodium hydroxide to the acid. These colours were green, blue and yellow. Write the colours in the correct order as they appeared. ====

<span style="font-family: Arial,Helvetica,sans-serif;"> **iii)** Discuss what effect adding the sodium hydroxide has on the pH of the solution in the boiling tube.
====<span style="font-family: Arial,Helvetica,sans-serif;">**2) a) i)** A student has one test tube containing magnesium oxide and another containing magnesium carbonate. Both substances are white powders. ====

<span style="font-family: Arial,Helvetica,sans-serif;">i**v)** Explain why the reactions of acids with carbonates and hydrogen carbonates are called neutralisation reactions.
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__ RATES OF REACTION AND PARTICLE THEORY __

 * [[image:11sciratesabsorb.jpg width="234" height="132" link="@http://www.absorblearning.com/chemistry/demo/units/LR1501.html"]] || [[image:11sciratesconc.jpg width="226" height="122" link="@http://www.absorblearning.com/chemistry/demo/units/LR1503.html"]] || [[image:11sciratessurface.jpg width="204" height="103" link="@http://www.absorblearning.com/chemistry/demo/units/LR1502.html"]] || [[image:11scitemp.jpg width="237" height="122" link="@http://www.absorblearning.com/chemistry/demo/units/LR1504.html"]] ||


 * = [[image:11scimarblechipsimulation.jpg width="296" height="378" link="@file:marble.dcr"]] || ====**<span style="color: #00b04f; font-family: Arial,Helvetica,sans-serif;">Try this marble chips simulation **====

**<span style="color: #00b04f; font-family: Arial,Helvetica,sans-serif;">to help with your understanding of Rates of Reaction **
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 * [[image:weebleyrates.jpg width="594" height="298" link="@http://factorsaffectingrates.weebly.com/"]] ||

**<span style="color: #00b04f; font-family: Arial,Helvetica,sans-serif;">to a question explaining Rates of Reaction **.
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NCEA PAST EXAM QUESTION: Rates of Reaction and particle theory
====<span style="font-family: Arial,Helvetica,sans-serif;">(a) Calcium carbonate pieces are placed in a flask and hydrochloric acid is added. Immediately a balloon is placed over the top of the flask. The balloon then starts to inflate. ====

<span style="font-family: Arial,Helvetica,sans-serif;">**(a)** State what factor affecting the rate of reaction is being investigated in this experiment.
====<span style="font-family: Arial,Helvetica,sans-serif;">**(b)** Explain what is happening in Experiment 1 in sections A, B, and C of the graph in terms of reaction rate. In your answer you should refer to particle collisions. ====

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 0%;">• explain how the products formed by the reaction lead to the decrease in mass of the beaker and conte
<span style="font-family: Arial,Helvetica,sans-serif; font-size: 0%;">The following experiment was carried out at 20°C and then repeated at 40°C.Marble chips (calcium carbonate) were added to hydrochloric acid in a conical flask. The mass and size of marble chips, and the concentration and volume of hydrochloric acid used, were the same for both experiments. The flask was connected to an inverted measuring cylinder in a basin of water, as shown in the diagram below. The volume of gas produced at the two different temperatures was measured for a few minutes and the results were used to sketch the graph shown below. State which line on the graph represents the reaction at 40°C and explain how you worked this out. In your answer you should: • identify which line represents the reaction at 40°C • explain why the line you have identified is the reaction at 40°C • give reasons for the different rates of reaction in terms of particles • explain why both lines end up horizontal.

• reaction rate.
====Marble chips (calcium carbonate) are added to dilute hydrochloric acid in a conical flask. The flask is connected to an inverted measuring cylinder in a trough of water, as shown in the diagram below. The volume of gas produced is measured over a few minutes, and the results used to sketch a graph.====

Discuss the effect on the reaction rate of using powdered marble with hydrochloric acid compared with using marble chips. In your answer, you should:

 * ====compare the rates of reaction====
 * ====explain the differences in the reaction rate by discussing how crushing the marble chips affects the number of particle collisions.====





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