CHEMISTRY   FORM 4  PREPARATION FOR STANDARDIZED TEST
QUESTION 1: An experiment is conducted to investigate the effect of temperature on the rate of reaction. 5 set of 50cm 3  ...
DOES THE TEMPERATURE AFFECT THE RATE OF REACTION BETWEEN SULPHURIC ACID AND MAGNESIUM RIBBON? <ul><ul><li>a) State a probl...
<ul><ul><li>b) Identify all the variables in this experiment.   </li></ul></ul><ul><ul><ul><li>i) Manipulated variable  </...
<ul><ul><li>c) State one suitable hypothesis for this experiment. </li></ul></ul>THE HIGHER THE TEMPERATURE , THE HIGHER T...
QUESTION 2: A group of students has carried out an experiment to determine the melting point of substance Y.  A boiling tu...
Time (min) 0 ½ 1 1½ 2 2½ 3 3½ Temp. ( o  C) 60.0 64.0 68.0 72.0 76.0 80.0 80.0 80.0 Time (min) 4 4 ½  5 5½ 6 6½ 7 7½ Temp....
a) Draw a graph of the temperature against time for the experiment and locate the melting point for  substance Y  [4 m]
 
b) Explain why there is no change in temperature from min 2½ to 6 min HEAT ABSORB BY THE PARTICLES  IS USE  TO OVERCOME TH...
c) Draw the arrangement of particles at 2 minutes of heating.  [1m]
QUESTION 3 Table 3 shows the  proton number and nucleon number for atom V,  W, X, Y and Z Atom Proton number Nucleon numbe...
<ul><li>Based on information given in Table 3, answer the following questions. </li></ul><ul><ul><li>a) What is meant by n...
<ul><ul><li>b) What is the number of neutron for particle W ?  [1 m] </li></ul></ul>1 <ul><ul><li>c) Write the electron ar...
<ul><ul><li>d) Draw the structure of atom X  [1 m] </li></ul></ul>
e) Which of the above atoms are isotopes? Explain your answer.  [2 m] V AND W. BOTH ATOMS HAVE  SAME PROTON NUMBER  BUT  D...
<ul><ul><li>f) How many valence electrons in atom X?  [1 m] </li></ul></ul>Electron arrangement: 2.1 Therefore; valence el...
Seminar form four= revision for selaras 1- april 2011
<ul><li>4) An experiment was conducted in order to determine the empirical formula of magnesium oxide. </li></ul><ul><ul><...
<ul><ul><li>Why must the magnesium ribbon be cleaned with sandpaper?  </li></ul></ul><ul><li>  </li></ul><ul><ul><li>Why d...
<ul><ul><ul><li>i) Calculate the mass of mg used.  </li></ul></ul></ul>MASS OF Mg  = (24.70-22.30)   = 2.4 g d) Descriptio...
<ul><ul><ul><li>ii) Calculate the mass of oxygen that reacts with magnesium.  </li></ul></ul></ul><ul><li>iii) Calculate t...
<ul><ul><ul><li>iv) Calculate the number of moles of oxygen that has reacted. </li></ul></ul></ul>MOLE OF OXYGEN = 1.6/16 ...
 
<ul><li>The reaction between hydrochloric acid and zinc carbonate was  written below.   hydrochloric acid  +  zinc carbona...
Rewrite the equation above as chemical equation.  [2 m] hydrochloric acid  +  zinc carbonate    zinc chloride + carbon di...
If 12.5 g of zinc carbonate react completely in the reaction above calculate, i)  the number of mole of  hydrochloric acid...
2HCl  +  ZnCO 3      ZnCl 2  +  CO 2  + H 2 O
ii)  the mass of zinc chloride obtained.  2HCl  +  ZnCO 3      ZnCl 2  +  CO 2  + H 2 O
iii) the vol of gas collected at room temp  2HCl  +  ZnCO 3      ZnCl 2  +  CO 2  + H 2 O
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Seminar form 4= revision on intro to chemistry, structure of atoms, formulae and chemical equation with answers

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Seminar form 4= revision on intro to chemistry, structure of atoms, formulae and chemical equation with answers

  1. 2. CHEMISTRY FORM 4 PREPARATION FOR STANDARDIZED TEST
  2. 3. QUESTION 1: An experiment is conducted to investigate the effect of temperature on the rate of reaction. 5 set of 50cm 3 of 1.0 mol dm -3 sulphuric acid is reacted with 5g of magnesium ribbon at a different temperature.
  3. 4. DOES THE TEMPERATURE AFFECT THE RATE OF REACTION BETWEEN SULPHURIC ACID AND MAGNESIUM RIBBON? <ul><ul><li>a) State a problem statement for above experiment. [2 m ] </li></ul></ul>
  4. 5. <ul><ul><li>b) Identify all the variables in this experiment. </li></ul></ul><ul><ul><ul><li>i) Manipulated variable </li></ul></ul></ul><ul><ul><ul><li>ii) Responding variable </li></ul></ul></ul><ul><ul><ul><li>iii) Controlled variable </li></ul></ul></ul>TEMPERATURE OF ACID RATE OF REACTION <ul><ul><ul><li>CONCENTRATION AND VOLUME OF ACID, MASS OF MAGNESIUM RIBBON </li></ul></ul></ul>
  5. 6. <ul><ul><li>c) State one suitable hypothesis for this experiment. </li></ul></ul>THE HIGHER THE TEMPERATURE , THE HIGHER THE RATE OF REACTION BETWEEN SULPHURIC ACID AND MAGNESIUM RIBBON.
  6. 7. QUESTION 2: A group of students has carried out an experiment to determine the melting point of substance Y. A boiling tube contained substance Y solid is heated in a water bath. The temperature of substance Y is recorded every 30 seconds. The result is as shown in table 2 below.
  7. 8. Time (min) 0 ½ 1 1½ 2 2½ 3 3½ Temp. ( o C) 60.0 64.0 68.0 72.0 76.0 80.0 80.0 80.0 Time (min) 4 4 ½ 5 5½ 6 6½ 7 7½ Temp. ( o C) 80.0 80.0 80.0 80.0 80.0 83.0 86.0 89.0
  8. 9. a) Draw a graph of the temperature against time for the experiment and locate the melting point for substance Y [4 m]
  9. 11. b) Explain why there is no change in temperature from min 2½ to 6 min HEAT ABSORB BY THE PARTICLES IS USE TO OVERCOME THE ATTRACTIVE FORCES BETWEEN THE PARTICLES
  10. 12. c) Draw the arrangement of particles at 2 minutes of heating. [1m]
  11. 13. QUESTION 3 Table 3 shows the proton number and nucleon number for atom V, W, X, Y and Z Atom Proton number Nucleon number V 1 1 W 1 2 X 3 7 Y 6 12 Z 20 40
  12. 14. <ul><li>Based on information given in Table 3, answer the following questions. </li></ul><ul><ul><li>a) What is meant by nucleon number? [1 m] </li></ul></ul>TOTAL NUMBER OF PROTON AND NEUTRON IN THE NUCLEUS OF AN ATOM
  13. 15. <ul><ul><li>b) What is the number of neutron for particle W ? [1 m] </li></ul></ul>1 <ul><ul><li>c) Write the electron arrangement for atom: [1 m] </li></ul></ul>V : 1 Z: 2.8.8.2
  14. 16. <ul><ul><li>d) Draw the structure of atom X [1 m] </li></ul></ul>
  15. 17. e) Which of the above atoms are isotopes? Explain your answer. [2 m] V AND W. BOTH ATOMS HAVE SAME PROTON NUMBER BUT DIFFERENT NUCLEON NUMBER OR V AND W. BOTH ATOMS HAVE SAME NUMBER OF PROTON BUT DIFFERENT NUMBER OF NEUTRON
  16. 18. <ul><ul><li>f) How many valence electrons in atom X? [1 m] </li></ul></ul>Electron arrangement: 2.1 Therefore; valence electron = 1
  17. 19. Seminar form four= revision for selaras 1- april 2011
  18. 20. <ul><li>4) An experiment was conducted in order to determine the empirical formula of magnesium oxide. </li></ul><ul><ul><li>a) Give the meaning of empirical formula. </li></ul></ul>IS THE FORMULA THAT GIVES THE SIMPLEST WHOLE NUMBER RATIO OF ATOM OF EACH ELEMENT IN A COMPOUND
  19. 21. <ul><ul><li>Why must the magnesium ribbon be cleaned with sandpaper? </li></ul></ul><ul><li>  </li></ul><ul><ul><li>Why does the crucible need to be covered with its lid as soon as the magnesium start burning? </li></ul></ul>TO REMOVE THE OXIDE LAYER TO PREVENT THE WHITE FUMES FROM ESCAPING
  20. 22. <ul><ul><ul><li>i) Calculate the mass of mg used. </li></ul></ul></ul>MASS OF Mg = (24.70-22.30) = 2.4 g d) Description Mass, g Mass of crucible + lid 22.30 Mass of crucible + lid + magnesium 24.70 Mass of crucible + lid + magnesium oxide 26.30
  21. 23. <ul><ul><ul><li>ii) Calculate the mass of oxygen that reacts with magnesium. </li></ul></ul></ul><ul><li>iii) Calculate the number of moles of magnesium used. </li></ul>MASS OF OXYGEN = 26.30-24.70 = 1.6 MOLE OF MAGNESIUM = 2.4 / 24 = 0.1
  22. 24. <ul><ul><ul><li>iv) Calculate the number of moles of oxygen that has reacted. </li></ul></ul></ul>MOLE OF OXYGEN = 1.6/16 = 0.1 <ul><ul><ul><li>v) Determine the empirical formula of magnesium oxide. </li></ul></ul></ul>Mg: O 0.1 : 0.1 1 : 1 MgO
  23. 26. <ul><li>The reaction between hydrochloric acid and zinc carbonate was written below. hydrochloric acid + zinc carbonate  zinc chloride + carbon dioxide + water </li></ul><ul><li>a) Write the chemical formula for zinc chloride.   </li></ul>
  24. 27. Rewrite the equation above as chemical equation. [2 m] hydrochloric acid + zinc carbonate  zinc chloride + carbon dioxide + water HCl + 2 ZnCO 3  ZnCl 2 + CO 2 + H 2 O
  25. 28. If 12.5 g of zinc carbonate react completely in the reaction above calculate, i) the number of mole of hydrochloric acid being used? [3m]
  26. 29. 2HCl + ZnCO 3  ZnCl 2 + CO 2 + H 2 O
  27. 30. ii) the mass of zinc chloride obtained. 2HCl + ZnCO 3  ZnCl 2 + CO 2 + H 2 O
  28. 31. iii) the vol of gas collected at room temp 2HCl + ZnCO 3  ZnCl 2 + CO 2 + H 2 O

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