Page 156 - Chemistry ICSE Class X

142 ICSE Chemistry – 10

Questions from Board Papers

Q 1. K .2) UVCPFU HQT NKSWGſGF RGVTQNGWO ICU 8CTKGVKGU QH .2) CTG OCTMGVGF KPENWFKPI C OKZVWTG QH RTQRCPG
CPF DWVCPG +H NKVTG QH VJKU OKZVWTG KU DWTPV ſPF VJG VQVCN XQNWOG QH ECTDQP FKQZKFG ICU CFFGF VQ VJG
atmosphere. Combustion reactions can be represented as: [ICSE 2010]
C H (g) + 5O (g) o 3CO (g) + 4H O (g)
8
2
2
3
2
2C H (g) + 13O (g) o 8CO (g) + 10H O(g)
2
2
4
10
2
(ii) Calculate the percentage of nitrogen and oxygen in ammonium nitrate.
[Relative molecular mass of ammonium nitrate is 80, H = 1, N = 14, O = 16].
Q 2. 4.5 moles of calcium carbonate are reacted with dilute hydrochloric acid. [ICSE 2010]
(i) Write the equation for the reaction.
(ii) What is the mass of 4.5 moles of calcium carbonate? (Relative molecular mass of calcium carbonate is 100).
(iii) What is the volume of carbon dioxide liberated at STP?
(iv) What mass of calcium chloride is formed? (Relative molecular mass of calcium chloride is 111)
(v) How many moles of HCl are used in this reaction?
Q 3. (i) Calculate the volume of 320 g of SO at STP. (Atomic mass : S = 32 and O = 16). [ICSE 2011]
2
(ii) State Gay-Lussac’s Law of combining volumes.
(iii) Calculate the volume of oxygen required for the complete combustion of 8.8 g of propane (C H ).
8
3
3
(Atomic mass : C = 12, O = 16, H = 1, Molar Volume = 22.4 dm at STP)
Q 4. (a) An organic compound with vapour density = 94 contains [ICSE 2011]
C = 12.67%, H = 2.13%, and Br = 85.11%. Find the molecular formula. [Atomic mass : C = 12, H = l, Br = 80]
(b) Calculate the mass of:
22
(i) 10 atoms of sulphur.
23
(ii) 0.1 mole of carbon dioxide. [Atomic mass : S = 32, C = 12, O = 16 and Avogadro’s number = 6 × 10 ]
Q 5. K NKVTGU QH J[FTQIGP EQODKPGU YKVJ NKVTGU QH PKVTQIGP VQ HQTO COOQPKC WPFGT URGEKſE EQPFKVKQPU CU
N (g) + 3H (g) o 2NH (g)
2
2
3
Calculate the volume of ammonia produced. What is the other substance, if any, that remains in the resultant
mixture ?
3
(ii) The mass of 5.6 dm of a certain gas at STP is 12.0 g. Calculate the relative molecular mass of the gas.
(iii) Find the total percentage of magnesium in magnesium nitrate crystals, Mg(NO ) .6H O.
2
3 2
[Mg = 24; N = 14; O = 16 and H = 1] [ICSE 2012]
Q 6. Concentrated nitric acid oxidises phosphorus to phosphoric acid according to the following equation:
P + 5HNO (conc.) o H PO + H O + 5NO 2
3
4
3
2
If 9.3 g of phosphorus was used in the reaction, calculate:
(i) Number of moles of phosphorus taken.
(ii) The mass of phosphoric acid formed.
(iii) The volume of nitrogen dioxide produced at STP. [H = 1, N = 14, P = 31, O = 16] [ICSE 2012]
Q 7. Solve the following:
3
(i) What volume of oxygen is required to burn completely 90 dm of butane under similar conditions of
temperature and pressure?
2C O + 13O o 8CO + 10H O
2
2
2
10
4
(ii) The vapour density of a gas is 8. What would be the volume occupied by 24.0 g of the gas at STP?
(iii) A vessel contains X number of molecules of hydrogen gas at a certain temperature and pressure. How many
molecules of nitrogen gas would be present in the same vessel under the same conditions of temperature and
pressure? [ICSE 2013]