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Atoms And Molecules
How many moles does 11 g of carbon dioxide make?
Molecular weight of carbon dioxide is 44g/mol.
Such that CO2 contains 1 carbon and 2 oxygen atom. Thus,
1 x12 +2x16 =44 (mass of carbon =12, mass of oxygen =16)
Now by dividing the given grams (11g) by the molecular weight of CO2:
11/44 =0.25 mol
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Calculate the number of molecules of sulphur (S8) present in 16 gm of solid sulphur.
Calculate the number of aluminium ions present in 0.56 gm of aluminium oxide.
Explain law of conservation of mass.
50 g of 10% lead nitrate is mixed with 50 g of 10% sodium chloride in a closed vessel. After the reaction has taken place, it was found that 6.83 g of lead chloride was precipitated. Besides, the reaction mixture contained 90 g water and sodium nitrate. Calculate the amount of sodium nitrate formed.
Name and explain two important laws of chemical combination ?
What are the postulates of Dalton’s atomic theory of matter?
Hydrogen and oxygen combine in two different ways to produce water and hydrogen peroxide. Which of Dalton’s law does this observation confirm? Explain.
State drawbacks of Dalton’s atomic theory of matter.
Give an illustration based on atomic theory for the difference between an element, compound and mixture.
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