1. The relative molecular mass of aluminium chlori de is 267 and its composition by mass is 20.3%o Al and 79.7% chlorine. Determine the empirical and molecular formulas of aluminium chloride.
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\2ms Date
Practice IB Bxam: Topic 1 Quantitative Chemistry
2Na(s) + 2H2O(l) - 2NaOH(aq) + Hz(g)
(Total4 marks)
2 . Sodiurn reacts with water as follows.
(Total 3 marks)
3 . An organic compound, A, containing only the elements carbon, hydrogen and oxygerr was analysed.
(a) A was found to contain 54.57o C and 9.17o Hby mass, the remainder being oxygen. Determine
the empirical formula of the compound. @ % O
(3) (b) A 0.230 g sam , when vaporized, had a volume of 0.0785 A*iat 95'C and 102 kPa.
Determine t
fu't
(3) (c) Determine the molecular formula of A using your answers from pafts (a) and (b).
ne/+ r/Fl!' . F ?rto Q = t(tl,:t) *ry(1,f0* /(:6a = ??.o;
/7= 87,8
( 1 ) (Total7 marks)
4. An organic compound A contains 62.07o by mass of carbon, 24.1o/o by mass of nitrogen, the remainder being hydrogen.
(i) Determine the percentage by mass of hydrogen and the empirical formula of A.
(3)
(ii) Define the term relative molecular Tass.
(iii) The relative rnolecular mass of A is 116. Determine the molecular formula of A.
(2)
( l ) ( To t a l 6 marks)
remaiuilu{, when 20.0 drn3 of propane reacts with 120.0 dmi of oxygen. All gas volumes are measured iffi" temperature arrd presiure.
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t? J-,s.
. . . ... . '. . . . ...' .. .. .. .. .. .. '.. . ... . ..g d n 3 e a L . / ,.@
Aog-Jnlc'ir r m= .
Propane and oxygen react according to the following equation.
C:Hs(g) + 5Oz(g) - 3COz(B) + 4H2O(g)
Calculate the volume of carbon dioxide and water vapour produced and the volume of oxygen
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6.
b Jt
i ; 4 tfu" ifl /,y'ett4€ '
(T o t a l 3 marks)
/ Ao,o -/o0. = leo.dn"oL
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7. (i)
C*lfY o*
Crocetin consists of the elements carbon, hydrogen and oxygen. Determine the empirical fomula of crocetin, if 1.00 g of crocetin forms 2.68 g of carbon dioxide and 0.657 g of water when it undergoes complete combustion.
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(ii) Determine the molecular formula of crocetin given that 0.300 rnole of crocetin has a mass of 98.5 g
mo/a /*t:l! 9F CrlaO 7 sta':pt {O:1D*zao =f,fl.//q U
n=ffi= L/
o
(2) (Total S marks)
-,ff;*^,ry(+ho)+
A solution containing ammonia requires 25.0 cml of 0. 100 rnol dm-3 hydrochloric acid to reach the
#ij n://uftt =rto/t*?/
1i; Write an equaiidl-or tlte reaction of ammonia with hydroclrloric acid
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( l )
(ii) Calculate the amount (in rnol) of hydrochloric acid atrd ammonia that react.
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(2) (\--Calculate the mass of ammonia in the solution.
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3.8% nitrogen and 46.2% carbon by massQAt 273llAnd lo+s g ofA occupies 462 cn3. Determine the empirical foffila of R.
molar mass of the compoutrd attd determine its molecular structure.
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3. fr tryol 4 / /4)?trrct /q :
(2) (Total5 marks)