Chemistry
(i) Name the metalloid(s) of period 3.
(ii) Define atomic size.
(iii) What would be seen on mixing a solution of calcium chloride with a solution of sodium carbonate? Write an equation also.
(iv) Write an equation for the preparation of a hydroxide of a metal which is
Green
Light blue
Periodic Table
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Answer
(i) Silicon [Si]
(ii) Atomic size is the distance between the centre of the nucleus of an atom and it's outermost shell.
(iii) White precipitate of calcium carbonate appears.
CaCl2 + Na2CO3 ⟶ 2NaCl + CaCO3
(iv)
Green : Iron [II] hydroxide
FeSO4 + 2NaOH ⟶ Na2SO4 + Fe(OH)2 ↓Light blue : Copper [II] hydroxide
CuSO4 + 2NaOH ⟶ Na2SO4 + Cu(OH)2 ↓
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Related Questions
If a crop of wheat replaces 30 kg of nitrogen per hectare of soil, what mass of the fertilizer calcium nitrate would be required to replace the nitrogen of a 5-hectare field ?
(at wt. N = 14, O = 16, Ca = 40)
(i) Oxygen oxidises ethyne to produce 8.4 litres of carbon dioxide at STP. Calculate the volume of ethyne used in this reaction.
2C2H2 + 5O2 ⟶ 4CO2 + 2H2O
(ii) A2B is the empirical formula of a compound which has vapour density 25. If atomic weight of A and B are 10 and 5 respectively. Find it's molecular formula.
Give a chemical test in each case to distinguish between the following pairs of chemicals.
(i) Sodium chloride solution and sodium nitrate solution.
(ii) Sodium sulphate solution and sodium chloride solution.
(iii) Calcium nitrate solution and zinc nitrate solution.
Calculate
(i) The volume of 2.5 moles of a gas X at stp.
(ii) The weight of 2.8 dm3 of a basic gas you have learnt, at STP.
(iii) The molecular weight of a gas Y whose 5.6 litres of volume at STP weighs 3.5 gms.
(at wt of C = 12, X = 14, H = 1, O = 16)