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• Calculate the percentage nitrogen content in the following ammonium salts. i) Ammonium sulphate (NH₄₎₂SO₄ ii) Urea, (NH₂₎₂CO N= 14, H=1, S=32, O=16, C=12
  

  Calculate the percentage nitrogen content in the following ammonium salts. i) Ammonium sulphate (NH₄₎₂SO₄ ii) Urea, (NH₂₎₂CO N= 14, H=1, S=32, O=16, C=12

  
  Form 3, Chemistry: Nitrogen and its Compounds

  Date posted: February 26, 2019.

• Write an equation to show the effect of heat on: i) Potassium nitrate, KNO₃ ii) silver nitrate, AgNO₃
  

  Write an equation to show the effect of heat on: i) Potassium nitrate, KNO₃ ii) silver nitrate, AgNO₃

  
  Form 3, Chemistry: Nitrogen and its Compounds

  Date posted: February 26, 2019.

• Zinc metal and hydrochloric acid react according to the following equation: Zn_(s) + 2Hcl_(aq)= ZnCl_2(aq) + H_2(g)
  

  Zinc metal and hydrochloric acid react according to the following equation: Zn_(s) + 2Hcl_(aq) = ZnCl_2(aq) + H_2(g) 1.96g of zinc metal were reacted with 100cm³ of 0.2m hydrochloric Acid. a) Determine the reagent that was in excess. b)...

  
  Form 3, Chemistry: Mole Concept

  Date posted: February 26, 2019.

• An atom of sodium is represented as shown below: (a) Calculate the number of neutrons in the nucleus of a sodium atom
  

  An atom of sodium is represented as: a) Calculate the number of neutrons in the nucleus of a sodium atom. b)Write the electronic configuration of a sodium atom

  
  Form 2, Chemistry: Structure of an Atom

  Date posted: February 26, 2019.

• Chlorine is element number 17 in the periodic table of elements. Write down the electron configuration of its: a) Atom b) Ion
  

  Chlorine is element number 17 in the periodic table of elements. Write down the electron configuration of its: a) Atom b) Ion

  
  Form 2, Chemistry: Structure of an Atom

  Date posted: February 26, 2019.

• Using dots (.) and crosses (x) to represent outermost electrons, draw diagrams to show bonding in. a)Carbon (IV) oxide b) NH₄⁺
  

  Using dots (.) and crosses (x) to represent outermost electrons, draw diagrams to show bonding in. a)Carbon (IV) oxide b) NH₄⁺

  
  Form 2, Chemistry: Structure and Bonding

  Date posted: February 26, 2019.

• An organic compound contains 24.24% carbon 4.04% hydrogen and the rest is chlorine a) Find its empirical formula. (C=12, H=1, Cl=35.5) b) Find its molecular formula if its R.M.M is 99.
  

  An organic compound contains 24.24% carbon 4.04% hydrogen and the rest is chlorine a) Find its empirical formula. (C=12, H=1, Cl=35.5) b) Find its molecular formula if its R.M.M is 99.

  
  Form 3, Chemistry: Mole Concept

  Date posted: February 26, 2019.

• Study the information in the table below and answer the questions that follow.
  

  Study the information in the table below and answer the questions that follow. i) Write the general formula of the hydrocarbons in the table. ii) Predict the relative...

  
  Form 3, Chemistry: Organic Chemistry 1

  Date posted: February 26, 2019.

• 6g of iron reacted with hydrogen chloride gas to form iron (II) chloride at S.T.P. Calculate the volume of the hydrogen chloride gas used. (Fe=56, molar gas volume at S.T.P=22.4dm³ )
  

  6g of iron reacted with hydrogen chloride gas to form iron (II) chloride at S.T.P. Calculate the volume of the hydrogen chloride gas used. (Fe=56, molar gas volume at S.T.P=22.4dm³ )

  
  Form 3, Chemistry: Mole Concept

  Date posted: February 26, 2019.

• When 27.8g of hydrated aluminium oxide, Al₂O₃.xH₂O, was heated to a constant mass, 20.6g of aluminium oxide was obtained. Determine the value of x (H=1, O=16, A=27)
  

  When 27.8g of hydrated aluminium oxide, Al₂O₃.xH₂O, was heated to a constant mass, 20.6g of aluminium oxide was obtained. Determine the value of x (H=1, O=16, A=27)

  
  Form 3, Chemistry: Mole Concept

  Date posted: February 26, 2019.

• An element N forms an ion N². This ion contains 18 electrons: a) State the period and the group of the periodic table that element N belongs.
  

  An element N forms an ion N². This ion contains 18 electrons: a) State the period and the group of the periodic table that element N belongs. b) Write the formula of the compound which would be formed if N reacts with bromine.

  
  Form 2, Chemistry: Structure and Bonding

  Date posted: February 26, 2019.

• An element Q consists of 3 isotopes of mass 28, 29, 30 and percentage abundance of 92.2%, 4.7%, 3.1% respectively. Determine the relative atomic mass of the element?
  

  An element Q consists of 3 isotopes of mass 28, 29, 30 and percentage abundance of 92.2%, 4.7%, 3.1% respectively. Determine the relative atomic mass of the element?

  
  Form 2, Chemistry: Chemical Families

  Date posted: February 26, 2019.

• During heating of a hydrated copper (II)sulphate crystals, the following readings were obtained: Mass of evaporating dish =300.0g, Mass of evaporating dish + hydrated salt = 305.0g, Mass of evaporating dish + anhydrous salt = 303.2g
  

  During heating of a hydrated copper (II)sulphate crystals, the following readings were obtained: Mass of evaporating dish =300.0g, Mass of evaporating dish + hydrated salt = 305.0g, Mass of evaporating dish + anhydrous salt = 303.2g Calculate the number of water of crystallization molecules in...

  
  Form 3, Chemistry: Mole Concept

  Date posted: February 26, 2019.

• Factorize: 6x² -13x + 6
  

  Factorize: 6x² -13x + 6

  
  Form 2, Mathematics: Quadratic Equations and Expressions

  Date posted: February 26, 2019.

• The cost of a pen is sh.X and that of a pencil is sh. 4 less than that of a pen. Find the combined cost of 4 pens and 5 pencils.
  

  The cost of a pen is sh.X and that of a pencil is sh. 4 less than that of a pen. Find the combined cost of 4 pens and 5 pencils.

  
  Form 1, Mathematics: Algebraic Expressions

  Date posted: February 26, 2019.

• Arrange the following fractions in descending order.
  

  Arrange the following fractions in descending order.

  
  Form 1, Mathematics: Fractions

  Date posted: February 26, 2019.

• Given that a=2, b=1, and c=3, find the value of
  

  Given that a=2, b=1, and c=3, find the value of

  
  Form 1, Mathematics: Algebraic Expressions

  Date posted: February 26, 2019.

• Solve for X in the equation below 32^{(x - 3)} ÷ 8^{(x - 4)} = 64 ÷ 2^x
  

  Solve for X in the equation below 32^{(x - 3)} ÷ 8^{(x - 4)} = 64 ÷ 2^x

  
  Form 2, Mathematics: Indices

  Date posted: February 26, 2019.

• Simplify the equation below
  

  Simplify the equation below

  
  Form 2, Mathematics: Quadratic Equations and Expressions

  Date posted: February 26, 2019.

• Find the equation of a line passing through (4, -3) and parallel to the line whose equation is 4y – 3x = 8.
  

  Find the equation of a line passing through (4, -3) and parallel to the line whose equation is 4y – 3x = 8.

  
  Form 2, Mathematics: Equations of Straight Lines

  Date posted: February 26, 2019.

• Find the value of x in (logx)² -15(logx) + 56 = 0
  

  Find the value of x in (logx)² -15(logx) + 56 = 0

  
  Form 3, Mathematics: Further Logarithms

  Date posted: February 26, 2019.

• Solve the simultaneous equation 3x – 4y =10 X + 3y = -1
  

  Solve the simultaneous equation 3x – 4y =10 X + 3y = -1

  
  Form 1, Mathematics: Linear Equations

  Date posted: February 26, 2019.

• Solve for the following 27^x +3^3x+1 =108
  

  Solve for the following 27^x +3^3x+1 =108

  
  Form 2, Mathematics: Indices

  Date posted: February 25, 2019.

• 1.60g of an oxide of Magnesium contain 0.84g by mass of Magnesium. Determine its empirical formula(Mg = 24.0, 16.0)
  

  1.60g of an oxide of Magnesium contain 0.84g by mass of Magnesium. Determine its empirical formula(Mg = 24.0, 16.0)

  
  Form 3, Chemistry: Mole Concept

  Date posted: February 25, 2019.

• Factorize completely; a²-15ab +36b²
  

  Factorize completely; a²-15ab +36b²

  
  Form 2, Mathematics: Quadratic Equations and Expressions

  Date posted: February 23, 2019.

• Find the sum of the first 30 terms of the series; 16+19+22……
  

  Find the sum of the first 30 terms of the series; 16+19+22……

  
  Form 3, Mathematics: Sequences and Series

  Date posted: February 23, 2019.

• The sides of a square are decreased by 5%. Find the percentage change in its area
  

  The sides of a square are decreased by 5%. Find the percentage change in its area.

  
  Form 3, Mathematics: Formula and Variation

  Date posted: February 23, 2019.

• Simplify the following
  

  Simplify $\frac{3}{3 - \sqrt 7}$

  
  Form 3, Mathematics: Surds

  Date posted: February 23, 2019.

• Given the following, find b
  

  Given $a=\begin{pmatrix}4\\3\\ \end{pmatrix}$ , $c=\begin{pmatrix}-2\\-5\\ \end{pmatrix}$ and 3a -2b +4c = $\begin{pmatrix}10\\-19\\ \end{pmatrix}$, find b

  
  Form 2, Mathematics: Vectors 1

  Date posted: February 23, 2019.

• Given that sin (x+60)⁰= cos 2x⁰.find the value of x
  

  Given that sin (x+60)⁰= cos 2x⁰.find the value of x

  
  Form 2, Mathematics: Trigonometry 1

  Date posted: February 23, 2019.