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

Class: Form 3

Subject: Chemistry

Topic: Mole Concept

Lesson Summary

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 hydrated copper (II)sulphate.(Cu =64.5, S = 32.0,O=16.0, H = 1.0)

---

More Video Lessons

---

• 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?

  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.

  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)

  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 )

  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 molecular mass of the hydrocarbon with 5 carbon atoms.
  iii) Determine the molecular formula of the hydrocarbon in (II) above and draw its structural formula (H=1.0, C = 12.0)

  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.

  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⁺

  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

  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

  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) Calculate the total volume of hydrogen gas that was liberated at S.T.P. Zn=65.4; molar gas volume = 22.4 litres at S.T.P.

  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

  Date posted: February 26, 2019

• 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

  Date posted: February 26, 2019

• 4.0g of magnesium carbonate have some impurity of magnesium sulphate were dissolved in 250cm³ of 1.0m HCL. 25cm³ of the resulting solution was found to require 28.8cm³ of 0.6M sodium hydroxide for complete neutralization.Calculate the number of moles of sodium hydroxide in 28.8cm³.
  

  4.0g of magnesium carbonate have some impurity of magnesium sulphate were dissolved in 250cm³ of 1.0m HCL. 25cm³ of the resulting solution was found to require 28.8cm³ of 0.6M sodium hydroxide for complete neutralization.Calculate the number of moles of sodium hydroxide in 28.8cm³.

  Date posted: February 26, 2019

• Draw the structural formulae of the following compounds: a) 2, 3 – dibromobutane b) 2, 3, 4 – trimethyl pentene c) 4 – chloro – 5 – methylhex – 2 –yne
  

  Draw the structural formulae of the following compounds:
  a) 2, 3 – dibromobutane
  b) 2, 3, 4 – trimethyl pentene
  c) 4 – chloro – 5 – methylhex – 2 –yne

  Date posted: February 26, 2019

• Balance the chemical equation given below C₃H₈ + O₂ ?H₂O + CO₂
  

  Balance the chemical equation given below
  C₃H₈ + O₂ ?H₂O + CO₂

  Date posted: February 26, 2019

• 30cm³ of hydrogen chloride gas diffuses through a porous pot in 20 seconds. How long would it take 42cm³ of sulphur(IV) oxide gas to diffuse through the same pot under the same conditions (H =1 Cl = 35.5 S = 32 O =16)
  

  30cm³ of hydrogen chloride gas diffuses through a porous pot in 20 seconds. How long would it take 42cm³ of sulphur(IV) oxide gas to diffuse through the same pot under the same conditions (H =1 Cl = 35.5 S = 32 O =16)

  Date posted: February 26, 2019

• Express 10,500 in terms of its prime factors and determine the smallest value of p such that 10,500p is a perfect cube
  

  Express 10,500 in terms of its prime factors and determine the smallest value of p such that 10,500p is a
  perfect cube

  Date posted: February 26, 2019

• Find the size of land each child got in the question below
  

  

  Date posted: February 26, 2019

• Without using tables evaluate
  

  Without using tables evaluate
  

  Date posted: February 26, 2019

• The cost of 5 skirts and 3 blouses is sh 1,750. Mueni bought three of the skirts and one of the blouses for sh 850.find the cost of each item.
  

  The cost of 5 skirts and 3 blouses is sh 1,750. Mueni bought three of the skirts and one of the blouses for sh 850.find the cost of each item.

  Date posted: February 26, 2019

View all video lessons