1.5_Reactions_AS90934

=1.5 AS 90934 Demonstrate understanding of aspects of chemical reactions (4 credits) =

reactions of elements with other elements

 * [[image:l1reactionsLiF.jpg width="343" height="220" link="@file:LiF.swf"]] || [[image:l1reactionsNaCl.jpg width="270" height="229" link="@file:NaCl.mov"]] || [[image:l1reactionsionic.jpg width="245" height="229" link="@file:ionic.swf"]] ||


 * [[image:l1reactionsFeandO.jpg width="226" height="231" link="@file:FeinO.mp4"]] || [[image:l1reactionsFeS.jpg width="312" height="229" link="@file:FeS.mov"]] || [[image:l1reactionsSO2.jpg width="271" height="228" link="@file:SandO.mp4"]] ||

NCEA PAST EXAM QUESTIONS on Combination
  ====Two reactions that burn brightly were shown to a class. In Reaction 1, the teacher demonstrated a strip of magnesium ribbon reacting with oxygen in air. ==== ====In Reaction 2, which was shown on a video, a grey powder, zinc, was mixed with yellow sulfur powder. The mixture was poured into a pile and heated. The mixed powders burst into flame and made a white powder. Analyse these reactions by answering the following questions. ====

Write a balanced symbol equation for each reaction.
====A teacher showed her class two video clips of chemical reactions. One was of a reaction between sodium metal and chlorine gas. The second was of a reaction between solid sulfur and chlorine gas. ==== ====(a) When the sodium metal reacted with chlorine gas, the video clip showed a shiny grey solid reacting with a yellow-green gas. The reaction resulted in the formation of white crystals. Link these observations to the reactants and products involved in this reaction. ====

(i) Identify the type of reaction that occurs: Give a reason for your choice:
====(ii) Describe any observations that would be made of this reaction, and link these to the substances involved in the reaction. Outline a test that could be used to confirm the presence of the product formed. ====

Different elements can be reacted together to form compounds with properties that are different to the original elements.
====The reaction of iron and sulfur to form iron(II) sulfide is an example of a combination reaction where all species (reactants and products) have different properties. Give a detailed account of this combination reaction. ====

In your answer you should:
====Chemical compounds are made by combining elements. For example, magnesium oxide is made by combining magnesium and oxygen, and carbon dioxide is made by combining carbon and oxygen. ==== ====<span style="font-family: Arial,Helvetica,sans-serif;">Compare and contrast the combination reaction that produces magnesium oxide with the combination reaction that produces carbon dioxide. In your answer, you should: ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">state the conditions required for this reaction to occur ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">describe any observations that would be made ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">outline the physical and chemical properties of EACH of the species ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">explain why the properties of the reactants differ from those of the products ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">write a balanced symbol equation for the reaction. ====

<span style="font-family: Arial,Helvetica,sans-serif;">discuss the similarities and differences between the TWO combination reactions.




<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">carbonates of copper, iron(II), calcium, barium, magnesium, zinc, and lead.

 * [[image:KIPbNO3.jpg width="365" height="274" link="@file:KIPbNO3.swf"]] || [[image:l1reactionsAgCl.jpg width="388" height="276" link="@http://employees.oneonta.edu/viningwj/modules/active_figure_05_04_Precipitation%20of%20AgCl.html"]] ||

<span style="font-family: Arial,Helvetica,sans-serif;">You may leave spectator ions out of your equations.
<span style="font-family: Arial,Helvetica,sans-serif;">

An experiment in a school laboratory involves adding colourless solutions together as shown in the diagram below.
<span style="font-family: Arial,Helvetica,sans-serif;">Analyse the reactions that occur in test tube A and test tube B. In your answer:

<span style="font-family: Arial,Helvetica,sans-serif;">• write a balanced ionic equation for each reaction.
<span style="font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;">• write a balanced ionic equation for the reaction.
====<span style="color: #000000; font-family: Arial,Helvetica,sans-serif;">A chemical reaction occurs when a solution of calcium nitrate is added to a solution of sodium hydroxide. Analyse this reaction by: ==== <span style="color: #f95725; display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="color: #000000; display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;">Two solutions are mixed in one beaker and two different solutions are mixed in another beaker, as shown below. A precipitate forms in one of the beakers.
 * ====<span style="color: #000000; font-family: Arial,Helvetica,sans-serif;">describing any observations that would be made ====
 * ====<span style="color: #000000; font-family: Arial,Helvetica,sans-serif;">identifying the products ====
 * ====<span style="color: #000000; font-family: Arial,Helvetica,sans-serif;">explaining what happens to EACH ion that is present in these two solutions ====
 * ====<span style="color: #000000; font-family: Arial,Helvetica,sans-serif;">writing a balanced symbol equation for this reaction. (Spectator ions may be omitted.) ====

<span style="font-family: Arial,Helvetica,sans-serif;">fully explain why no other precipitate will form in that beaker.
<span style="font-family: Arial,Helvetica,sans-serif;">

When a fresh solution of iron(II) sulfate is added to a solution of potassium carbonate, a precipitate forms. Discuss the process of this precipitation reaction.
FeSO 4 (//aq//) + K 2 CO 3 (//aq//) → ? In your answer: Refer to the solubility rules provided in the Resource Booklet.
 * State any observations you would make.
 * Explain what happens to **each ion** present in the solutions used in this reaction.
 * Write the name or formula of the precipitate formed.
 * Write a balanced equation (spectator ions may be omitted).

<span style="font-family: Arial,Helvetica,sans-serif;">Discuss what happens when a solution of potassium hydroxide is added to a solution of calcium nitrate.
<span style="font-family: Arial,Helvetica,sans-serif;">KOH(aq) + Ca(NO3)2(aq) → ?

<span style="font-family: Arial,Helvetica,sans-serif;">Each of the following equations shows what could happen when two solutions are mixed in a beaker.
<span style="font-family: Arial,Helvetica,sans-serif;">Reaction 1 Pb(NO3)2 + 2NaCl → PbCl2 + 2NaNO3Reaction 2 FeSO4 + Mg(NO3)2 → Fe(NO3)2 + MgSO4

<span style="font-family: Arial,Helvetica,sans-serif;">(b) Write a balanced equation for the formation of ONE precipitate identified in (a) above. Spectator ions may be omitted from ionic equations.
<span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">2) lead nitrate + potassium chloride → +

<span style="font-family: Arial,Helvetica,sans-serif;">(b) State what type of reaction is occurring.
====<span style="font-family: Arial,Helvetica,sans-serif;">(c) Discuss the chemistry of this reaction. Your discussion should refer to the observations you made in part (a). Include a balanced equation in your answer. Spectator ions may be omitted. ==== ====<span style="font-family: Arial,Helvetica,sans-serif;">The following solutions are mixed in the pairs shown. Use the solubility rules in your Resource Booklet to identify the precipitate (if any) that is formed for each pair. ====

<span style="font-family: Arial,Helvetica,sans-serif;">(a) Write the name of the precipitate or, if none is formed, write no precipitate.
====<span style="font-family: Arial,Helvetica,sans-serif;">(b) Write a balanced equation for the formation of ONE precipitate identified in question (a)above. Spectator ions may be omitted from ionic equations. ==== ====<span style="font-family: Arial,Helvetica,sans-serif;">The following pairs of solutions are mixed. Use the solubility rules in your Resource Booklet to identify the precipitate (if any) that is formed. Write the name of the precipitate or, if none is formed, write no precipitate. ==== ====<span style="font-family: Arial,Helvetica,sans-serif;">Write a balanced equation for the formation of ONE precipitate identified in question (a) above. Spectator ions may be omitted from ionic equations. ==== <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">magnesium chloride + sodium hydroxide → + _ ====<span style="font-family: Arial,Helvetica,sans-serif;">Iron (II) nitrate solution is added to sodium hydroxide solution in a test tube. (i) Describe ONE observation that you would make as the reaction occurs. ====

1) Complete the table below by writing the name of the precipitate, or no precipitate if one is not formed. Use the Solubility Rules in the Resource Booklet.
<span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;">sodium hydroxide + → sodium sulfate + magnesium hydroxide <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;">CaCl2 (aq) + → CaSO4 (s) + NaCl (aq) <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;">Cu(NO3)2 (aq) + NaOH (aq) → +

<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif;">catalytic decomposition of hydrogen peroxide

 * [[image:l1reactionsCuHCO3.jpg width="333" height="241" link="@file:Cu(HCO3)2.swf"]] || [[image:l1reactionsCuSO4.jpg width="190" height="240" link="@http://learnthings.co.za/content/secondary/Home/Lessons/Science/Chemistry/Grade10/chemicalr/reversibl/heatingah/default.htm"]] ||


 * [[image:l1reactionselephanttoothpaste.jpg width="181" height="239" link="@file:H2O2.mp4"]] || ==<span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;">[[image:l1reactionsH2O2.jpg width="418" height="233" link="@https://www.youtube.com/watch?v=nkeniDKGs6Q"]] == ||

<span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;">NCEA PAST EXAM QUESTIONS on Decomposition
<span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;"> Two decomposition reactions were set up in the laboratory.
 * Reaction 1: ** Solid sodium hydrogen carbonate, NaHCO 3, was heated over a Bunsen burner flame.

<span style="font-family: Arial,Helvetica,sans-serif;">Write a balanced symbol equation for the decomposition of sodium hydrogen carbonate, NaHCO3.
(c) Compare the observations you would make for the reactions in the two test tubes. Link these observations to the reactants and products involved in the reactions. (d) Write a balanced symbol equation for the reaction in test tube 1.
 * Reaction 2 ** : Test tube 1 and test tube 2 were both half-filled with hydrogen peroxide solution, H 2 O 2 . Some powdered manganese dioxide, MnO 2, was then added to test tube 1.

Compare and contrast the decomposition reactions shown in ** Reaction 1 ** (sodium hydrogen carbonate, NaHCO 3 ) and **Reaction 2** (hydrogen peroxide, H 2 O 2 ).
Two calcium compounds were heated over a Bunsen burner in a school laboratory. In the first experiment, shown in the diagram below, **calcium carbonate** was heated. In the second experiment, **calcium hydroxide** was heated. ====<span style="font-family: Arial,Helvetica,sans-serif;">Compare and contrast the reaction that occurs when solid calcium carbonate is strongly heated, with the reaction that occurs when solid calcium hydroxide is strongly heated. In your answer: ====

<span style="font-family: Arial,Helvetica,sans-serif;">• write a balanced symbol equation for each reaction.
<span style="font-family: Arial,Helvetica,sans-serif; line-height: 0px; overflow: hidden;"> 1) In a reaction, a boiling tube with copper carbonate powder is heated over a Bunsen burner flame.

<span style="font-family: Arial,Helvetica,sans-serif;">• write a balanced symbol equation for the reaction involving hydrogen peroxide.
<span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;"> ====<span style="font-family: Arial,Helvetica,sans-serif;">Students in a laboratory are asked to identify three powders by using a thermal decomposition reaction. The powders are copper hydroxide, Cu(OH)2, sodium carbonate, Na2CO3, and sodium hydrogen carbonate, NaHCO3. Explain how you could identify each of these powders by heating them. ====

<span style="font-family: Arial,Helvetica,sans-serif;">Your answer should include:
====<span style="font-family: Arial,Helvetica,sans-serif;">1) A group of students carried out an investigation into whether or not various solid carbonates undergo thermal decomposition. The students found that copper (II) carbonate did decompose when heated. Discuss the thermal decomposition of copper (II) carbonate. In your answer, you should: ==== ====<span style="font-family: Arial,Helvetica,sans-serif;">2) A solution of hydrogen peroxide decomposes into water and oxygen gas very slowly.A catalyst can be used to speed up this reaction. The sketch graph below shows the volume of oxygen produced over the course of time when a catalyst is use ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">any observations that would be made ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">any tests that would be carried out on products formed to confirm their presence ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">balanced symbol equations for any reactions occurring. ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">name the products formed ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">describe what would be observed during the decomposition ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">explain why a solution of limewater would be useful in this investigation ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">fully explain what happens to the carbonate ions in the decomposition reaction ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">write a balanced chemical equation for the decomposition reaction. ====

[[image:NCEA2010.jpg]]
====<span style="color: #221e1f; font-family: Arial,Helvetica,sans-serif;">Three carbonate compounds, sodium carbonate, zinc carbonate and copper carbonate, are heated one at a time in the apparatus shown in the diagram below. ====



<span style="font-family: Arial,Helvetica,sans-serif;">(b) Discuss the differences in the decomposition of sodium carbonate, zinc carbonate, and copper carbonate.
====<span style="font-family: Arial,Helvetica,sans-serif;">Some green copper(II) carbonate powder is heated in a boiling tube over a Bunsen flame. A burning splint inserted into the top of the boiling tube goes out. ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">Describe the differences between the reactions of the three carbonates. ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">Link the relevant species to the observations you recorded in the table in (a). ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">Include any balanced equations. ====

<span style="font-family: Arial,Helvetica,sans-serif;">Discuss the chemistry in this thermal decomposition reaction by:
==== Some dry copper(II) hydroxide was heated in a test tube over a Bunsen burner. When a piece of blue cobalt chloride paper was held in the mouth of the test tube, the paper turned pink. Discuss what happened in the reaction in the **test tube**. ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">describing ONE other observation that would be made during this reaction ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">linking the observations to the relevant chemical species ====
 * ====<span style="font-family: Arial,Helvetica,sans-serif;">writing a balanced equation. ====

(b) Fully describe the observations that would be expected if this reaction was carried out in a school laboratory. Remember to link your observations to the substances involved.
====<span style="font-family: Arial,Helvetica,sans-serif;">A group of students carried out an investigation into the thermal decomposition of the following solid carbonates: sodium carbonate, calcium carbonate, and copper carbonate. ====

<span style="font-family: Arial,Helvetica,sans-serif;">1) copper hydroxide (heat) →
====<span style="font-family: Arial,Helvetica,sans-serif;">2) A sample of copper carbonate is heated strongly in a boiling tube ﬁtted with a delivery tube. The gas formed is bubbled into limewater. (See the diagram below.) ====



<span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;">displacement of metals ions in solution by other metals

 * [[image:l1reactionsdisplacement.jpg width="347" height="222" link="@file:chemicalminds/reactseries.swf"]] || [[image:discodisplacement.jpg width="228" height="209" link="@file:chemicalminds/disco_dispacement.ppt"]] ||


 * [[image:l1reactionsCuAg.jpg width="346" height="229" link="@file:chemicalminds/Cu(HCO3)2.swf"]] || [[image:l1reactionsmetals.jpg width="334" height="230" link="@file:chemicalminds/metalreactivity.swf"]] ||

<span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;"> NCEA PAST EXAM QUESTIONS on Displacement
<span style="color: #f95725; font-family: Arial,Helvetica,sans-serif;"> ====<span style="color: #221e1f; font-family: Arial,Helvetica,sans-serif;">A zinc rod was placed in a solution of copper sulfate, and another zinc rod was placed in a solution of magnesium sulfate. Both were left for one week ====

<span style="font-family: Arial,Helvetica,sans-serif;">Describe any observations that would be made for each beaker. Identify the type of reaction that is occurring above.
====<span style="font-family: Arial,Helvetica,sans-serif;">Explain any difference in the observations made in Beaker 1 and Beaker 2 by linking your observations to the type of reaction occurring, and the reactants and products involved. Write ONE balanced ionic equation for a reaction from (a). ====

<span style="font-family: Arial,Helvetica,sans-serif;">(ii) Write a balanced ionic equation for the reaction you have chosen above
====<span style="color: #221e1f; font-family: Arial,Helvetica,sans-serif;">A spotting tile was set up, as shown in the diagram below, to investigate the reaction of small pieces of cleaned metals with a small volume of different metal nitrate solutions. ====

<span style="font-family: Arial,Helvetica,sans-serif;">Complete the table below to identify which reactions will occur. You may refer to the activity series in the resource booklet.
<span style="font-family: Arial,Helvetica,sans-serif;">(b) Identify the type of reaction that is occurring on the spotting tile, and justify your choice. In your answer:

<span style="font-family: Arial,Helvetica,sans-serif;">identify the reaction you have selected
====<span style="font-family: Arial,Helvetica,sans-serif;">describe any observations that would be made in the selected reaction, and link your observations to the reactants and products involved in the reaction ====

<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;">An experiment in the laboratory involves placing an iron nail in copper sulfate (CuSO4) solution and a copper nail in iron(II) sulfate (FeSO4) solution. ====

<span style="font-family: Arial,Helvetica,sans-serif;">(a) Describe any observations that would be made the next day.
====<span style="font-family: Arial,Helvetica,sans-serif;">(b) (i) Identify the type of reaction that occurs and give a reason for your choice. You may refer to the activity series provided in the resource booklet. ====

<span style="font-family: Arial,Helvetica,sans-serif;">(ii) Write a balanced ionic equation for ONE reaction that occurs.
====<span style="font-family: Arial,Helvetica,sans-serif;"> Cleaned pieces of the metals iron (Fe), lead (Pb) and tin (Sn) were placed in solutions of iron(II) sulfate (FeSO4), lead nitrate (Pb(NO3)2) and tin sulfate (SnSO4), as shown in the table below: ==== <span style="color: #f95725; font-family: Arial,Helvetica,sans-serif; line-height: 0px; overflow: hidden;">

Discuss the chemistry of this displacement reaction. In your answer, you should:
====<span style="font-family: Arial,Helvetica,sans-serif;">Some grey powdered magnesium was added to a green solution of iron (II) sulfate in a beaker, and mixed well. The green colour of the solution faded and the grey powder disappeared. A new dark grey solid formed on the bottom of the beaker. ====
 * ====describe the physical changes that would occur====
 * ====relate each change to the chemical(s) involved====
 * ====fully explain why the displacement reaction occurs====
 * ====write a balanced **ionic** equation for the reaction.====

<span style="font-family: Arial,Helvetica,sans-serif;">(i) State what type of reaction this is.
====<span style="font-family: Arial,Helvetica,sans-serif;">(ii) Discuss what happened in this reaction. Your answer should link the reactants and products involved in the reaction to the observations made. ====

<span style="font-family: Arial,Helvetica,sans-serif;">Include an appropriate balanced equation in your answer. Spectator ions may be omitted.
<span style="font-family: Arial,Helvetica,sans-serif; line-height: 0px; overflow: hidden;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1) aluminium + silver nitrate → ___ +__ __

A piece of **copper** is placed in a solution of **silver nitrate**.
(i) Describe TWO observations that would be made.



[[image:chemicalminds/crystalball.gif]]




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<span style="color: #f95727; font-family: Arial,Helvetica,sans-serif; text-align: center;">//SciPAD// (2015) Jason Rendle, Silverback Academic Media
<span style="color: #f95727; display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">