Potassium nitrate crystals in a test-tube were heated strongly for some time. State the observation made: (a) When a glowing splint is introduced into the test-tube...

Potassium nitrate crystals in a test-tube were heated strongly for some time. State the observation made:
(a) When a glowing splint is introduced into the test-tube during the heating
(b) At the end of the heating

---

(a) Glowing splint is relighted/rekindles

(b) Pale yellow solid

---

maurice.mutuku answered the question on October 16, 2019 at 07:03

Exams With Marking Schemes

• Grade 1
• Grade 2
• Grade 3
• Grade 4
• Grade 5
• Grade 6
• Grade 7
• Grade 8
• Grade 9
• PP1
• PP2
• Playgroup
• Form 1
• Form 2
• Form 3
• Form 4

Related Questions

---

• Study the flow chart below and answer the questions that follow (Solved)
  

  Study the flow chart below and answer the questions that follow
  
  a) Identify ;
  i) gases C and B
  ii) Ions likely to be presented in solid A

  Date posted: October 16, 2019 .    Answers (1)

• A piece of marble chips was strongly heated in air for about 30 minutes. Some drops of water were added drop by drop to the... (Solved)
  

  A piece of marble chips was strongly heated in air for about 30 minutes. Some drops of water were added drop by drop to the product when it was still warm.
  Using equation, explain:
  (i) What happens when the piece of marble chips is heated?
  (ii) The reaction that takes place when water is added to the final warm product.

  Date posted: October 16, 2019 .    Answers (1)

• A student poured sodium iodide solution into a small portion of solution Q, a yellow precipitate was formed. Which ion was most likely in solution Q? (Solved)
  

  A student poured sodium iodide solution into a small portion of solution Q, a yellow precipitate was formed.
  Which ion was most likely in solution Q?
  

  Date posted: October 16, 2019 .    Answers (1)

• When exposed to air, crystals of hydrated sodium carbonate loses water of crystallizations;- (i) Name this process (ii) Write the formula of hydrated sodium carbonate (Solved)
  

  When exposed to air, crystals of hydrated sodium carbonate loses water of crystallizations;-
  (i) Name this process
  (ii) Write the formula of hydrated sodium carbonate

  Date posted: October 16, 2019 .    Answers (1)

• You are provided with the following:- solid lead (II) nitrate, magnesium oxide powder,dilute sulphuric (VI)acid and distilled water. Describe how you can prepare a dry... (Solved)
  

  You are provided with the following:- solid lead (II) nitrate, magnesium oxide powder,dilute sulphuric (VI)acid and distilled water. Describe how you can prepare a dry sample of lead (II) sulphate

  Date posted: October 16, 2019 .    Answers (1)

• The scheme below shows some reactions starting with magnesium oxide. Study it and answer the questions that follow:- (Solved)
  

  The scheme below shows some reactions starting with magnesium oxide. Study it and answer the questions that follow:-
  
  (i) Name the reagents used in steps 2 and 4
  (ii) Write an equation for the reaction in step 3
  (iii) Describe how a solid sample of anhydrous magnesium carbonate is obtained in step 5

  Date posted: October 16, 2019 .    Answers (1)

• Starting with sodium oxide, describe how a sample of crystals of sodium hydrogen carbonate may be prepared (Solved)
  

  Starting with sodium oxide, describe how a sample of crystals of sodium hydrogen carbonate may be prepared

  Date posted: October 16, 2019 .    Answers (1)

• Study the information in the table below and answer the questions that follow:- (Solved)
  

  Study the information in the table below and answer the questions that follow:-
  
  (a) Complete the table by filling in the blank spaces (i) , (ii) (iii), and (iv)
  (b) Identify the particles which are electrically charged

  Date posted: October 16, 2019 .    Answers (1)

• The table below shows properties of period three chlorides (Solved)
  

  The table below shows properties of period three chlorides
  
  Explain why AlCl3 solid has a much lower boiling point than MgCl2 solid

  Date posted: October 16, 2019 .    Answers (1)

• Below is a table oxides of some period three elements (Solved)
  

  Below is a table oxides of some period three elements
  
  (a) Give the systematic name of Cl₂O
  (b) Explain why Na₂O exists as a solid whereas SO₂ is a gas at room temperature

  Date posted: October 16, 2019 .    Answers (1)

• In terms of structure and bonding, explain why diamond is the hardest naturally occurring substance (Solved)
  

  In terms of structure and bonding, explain why diamond is the hardest naturally occurring substance

  Date posted: October 16, 2019 .    Answers (1)

• Use the scheme to answer the questions that follow: (Solved)
  

  Use the scheme to answer the questions that follow:
  
  (a) Identify solid N
  (b) Write a balanced equation for the formation of Q
  (c) Write the formula of the complex ion formed when sodium hydroxide is added to solution L in excess

  Date posted: October 16, 2019 .    Answers (1)

• Name the type of bonding and structure found in: - (a) Ice (b) Magnesium chloride (Solved)
  

  Name the type of bonding and structure found in: -
  (a) Ice
  (b) Magnesium chloride

  Date posted: October 15, 2019 .    Answers (1)

• The atomic number of element P is 11 and that of Q is 8 a) Write down the possible formula of the compound formed between P... (Solved)
  

  The atomic number of element P is 11 and that of Q is 8
  a) Write down the possible formula of the compound formed between P and Q
  b) Using dots (·) and crosses(x) to represent electrons draw a diagram to represent the bonding in the compound in (a) above

  Date posted: October 15, 2019 .    Answers (1)

• The table below shows the elements in the third period, the oxides of the third period and their properties. The letters are not the actual... (Solved)
  

  The table below shows the elements in the third period, the oxides of the third period and their properties. The letters are not the actual symbols of the elements. Study the information and answer
  the questions that follow:
  
  i) Complete the table above
  ii) Explain the trend in the atomic radius across the period
  iii) Explain why the oxide of element V does not exist

  Date posted: October 15, 2019 .    Answers (1)

• Study the information in the table below and answer the questions that follow: (The letters do not represent the actual symbols of the elements) (Solved)
  

  Study the information in the table below and answer the questions that follow:
  (The letters do not represent the actual symbols of the elements)
  
  (i) What is meant by ionization energy?
  (ii) Element R has the lowest ionization energy. Explain
  (iii) When a piece of element Q is placed on water it melts and a hissing sound is produced as it moves on the water surface. Explain these observations
  (iv) Write the equation for the reaction between element Q and water

  Date posted: October 15, 2019 .    Answers (1)

• Part of the periodic table is given below study it and answer the questions that follow. The letters do not represent the actual elements (Solved)
  

  Part of the periodic table is given below study it and answer the questions that follow.
  The letters do not represent the actual elements
  
  (i) What type of bond is formed when Y reacts with Z. Explain
  (ii) Explain the difference in the atomic radii of element A and B
  (iii) Explain the difference in the reactivity of Z and B

  Date posted: October 15, 2019 .    Answers (1)

• The grid below represents part of the periodic table. The letters do not represent actual symbols of the elements. Study it and answer the questions... (Solved)
  

  The grid below represents part of the periodic table. The letters do not represent actual symbols of the elements. Study it and answer the questions that follow:-
  
  (a) What type of bond would you expect in the compound formed between H and F. Explain
  (b) (i) Which of the elements J and M will have a greater atomic radius? Explain
  (ii) Elements F and N are in the same group of periodic table. How do their atomic
  radius compare? Explain
  (c) An element W has atomic number 15. Indicate the position it would occupy in the table above
  (d) What is the name given to elements X – Z?
  (e) Why is J used in electric cables where Q is not
  (f) P and J are termed as metalloids. What does the term metalloid mean?
  (g) How would you expect the reactivity of H and M to compare? Explain

  Date posted: October 15, 2019 .    Answers (1)

• Sodium metal tarnishes when exposed to the air where a white powder is formed on its surface. A small piece of this sodium metal was dropped... (Solved)
  

  Sodium metal tarnishes when exposed to the air where a white powder is formed on its
  surface. A small piece of this sodium metal was dropped into 25g of ethanol and 1200cm³
  of hydrogen gas was evolved at r.t.p. The unreacted ethanol was evaporated and a white
  solid remained. (Na=23, molar gas volume at r.t.p = 24dm³, C=12, O =16, H=1)
  (a) Write a chemical equation for the reaction between ethanol and sodium metal
  (b) Determine the mass of sodium that reacted with ethanol
  (c) What mass of ethanol evaporated?
  (d) The ethanol was evaporated at 80^oC, while the white solid remained unaffected at this
  temperature. What is the difference in structure of ethanol and the white solid?
  (II) (a) Name an inorganic liquid which liberates hydrogen gas with sodium metal
  (b) What two differences would you observe if similar pieces of sodium were dropped
  separately into small beakers containing equal amount of ethanol and the liquid
  named in (II)(a) above respectively

  Date posted: October 15, 2019 .    Answers (1)

• Explain the following observations:- (i) NaCl allows electric current to pass through them in molten state (ii) Graphite is a non-metal yet it is a conductor of... (Solved)
  

  Explain the following observations:-
  (i) NaCl allows electric current to pass through them in molten state
  (ii) Graphite is a non-metal yet it is a conductor of electricity

  Date posted: October 15, 2019 .    Answers (1)