2.85g of an oxide of copper gave 2.52g of copper on reduction and 1.90g of another oxide gave 1.52g of copper on reduction. The data above illustrates the law of?
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1997
35 cm3 of hydrogen was sparked with 12 cm3 of oxygen at 110°C and 760mm Hg to produce steam. What percentage of the total volume of gas left after the reaction is hydrogen?
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1997
In the periodic table, what is the property that decreases along the periodic and increases down the group?
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1997
The electron configuration of two elements with similar chemical properties are represented by?
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1997
The temperature of a body decreases when drops of liquid placed on it evaporate because?
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1997
A mixture of 0.20 mole of Ar, 0.20 mole of N2 and 0.30 mole of He exerts a total pressure of 2.1 atm. The partial pressure of He in the mixture is?
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1997
An element, X, forms a volatile hydride XH3 with a vapour density of 17.0. The relative atomic mass of X is?(H = 1)
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1997
On recrystallization, 20g of magnesium tetraoxosuphate (IV) forms 41 g of magnesium tetraoxosulphate (IV) crystals, MgSO4. yH2O. The value of y is?(Mg = 24, S = 32, O = 16, H = 1)
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1997
200 cm3 of air was passed over heated copper in a syringe several times to produce copper (II) oxide.When cooled, the final volume of air recorded was 158cm3. Estimate the percentage of oxygen in the air?
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1997
If 30cm3 of oxygen diffuses through porous plug in 7s, how long will it take 60 cm3 of chlorine to diffuse through the same plug?
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1997
Oxygen is a mixture of two isotopes O and O with relative abundances of 90% and 10% respectively. The relative atomic mass of oxygen is?
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1997
Two elements, P and Q with atomic numbers 11 and 8 respectively , combine chemically to form the compound PxQY. The respective values of x and y are?
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1997
Which of the aqueous solutions with the pH values below will liberate hydrogen when it react with magnesium metals?
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1997
The hydroxyl ion concentrated, (OH-), in a solution of sodium hydroxide of pH 10.0 is?
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1997
A saturated solution of AgCl was found to have a concentration of 1.30 x 10-5 mol dm-3. The solubility product of AgCl therefore is?
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1997
A major process involved in the softening of hard water is the?
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1997
Which of the following gases is the most dangerous pollutant?
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1997
2H2S(g) + SO2(g) + H2O(l) → 3S(s) + 3H2O(l)..........(I)3CuO(s) + 2NH3(g) → 3Cu(s) + 3H2O(l) + N2(g).........(II)In the equations above, the oxidizing agent (I) and the reducing agent in (II) respectively are?
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1997
What is the oxidation number of Z in K3ZCl6?
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1997
How many Faraday of electricity are required to deposit 0.20 mole of nickel, if 0.10 Faraday of electricity deposited 2.98g of nickel during electrolysis of its aqueous solution?(Ni = 58.7, 1F = 96 500 C mol-)