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- 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)= ZnCl2(aq) + H2(g)
Zinc metal and hydrochloric acid react according to the following equation:
Zn(s) + 2Hcl(aq) = ZnCl2(aq) + H2(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
- Abdi sold a radio costing ksh 3,800 at a profit of 20%.He earned a commission of 22.5% on the profit.Find the amount he earned.
Abdi sold a radio costing ksh 3,800 at a profit of 20%.He earned a commission of 22.5% on the profit.Find the amount he earned.
Date posted: February 26, 2019
- Musa paid sh 180 for a shirt after getting a discount of 10%.The shopkeeper made a profit of 20% on the sale of this shirt.What percentage profit would the shopkeeper have made if no discount was allowed?.
Musa paid sh 180 for a shirt after getting a discount of 10%.The shopkeeper made a profit of 20% on the sale of this shirt.What percentage profit would the shopkeeper have made if no discount was allowed?.
Date posted: February 26, 2019