Dpp 02 mole_concept_jh_sir-3572

PAGE NO. # 1
ETOOS ACADEMY Pvt. Ltd
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CHEMISTRY
DAILY PRACTICE PROBLEMS
D P P
COURSE NAME : UDAY (UB) DATE : 10.06.2013 to 15.06.2013 DPP NO. 01 TO 4
TARGET
JEE (ADVANCED) : 2015
* Marked Questions are having more than one correct option.
DPP No. # 1
1. A quantity of aluminium has a mass of 54.0 g. What is the mass of the same number of magnesium
atoms?
(A) 12.1 g (B) 24.3 g (C) 48 g (D) 97.2 g
2. The charge on 1 gram ions of Al3+
is :
(A)
27
1
NA
e coulomb (B)
3
1
× NA
ecoulomb (C)
9
1
× NA
ecoulomb (D) 3 × NA
ecoulomb
3. The density of water at 4°C is 1.0 × 103
kg m–3
. The volume occupied by one molecule of water is
approximately :
(A) 3.0 × 10–23
mL (B) 6.0 × 10–22
mL (C) 3.0 × 10–21
mL (D) 9.0 × 10–23
mL
4. The number of molecules of water in 333 g of Al2
(SO4
)3
. 18H2
O is :
(A) 18.0 × 6.02 × 1023
(B) 9.0 × 6.02 × 1023
(C) 18.0 (D) 36.0
5. From 392 mg of H2
SO4
, 1.204 × 1021
molecules are removed. How many moles of H2
SO4
are left ?
(A) 2.0 × 10–3
(B) 1.2 × 10–3
(C) 4.0 × 10–3
(D) 1.5 × 10–3
6. In which of the following pairs do 1 gm of each have an equal number of molecules ?
(A) N2
O and CO (B) N2
and C3
O2
(C) N2
and CO (D) N2
O and CO2
Comprehension (Q. No. 7 to 9)
Equal number of atoms are contained in one gram atomic weight of each element, and that the same
number of molecules is found in one gram molecular weight of any compound. The terms gram atomic
weight and gram molecular weight are used to refer to a fixed number (Avogadro's number 6.023 x 1023
) of
particle. The term mole stands for the amount of material which contains these number of particles.
7. If 12 g of C12
has equal number of atoms as Avogadro's number what mass of 2
He4
will contain same
number of atoms ?
(A) 2 g (B) 4 g (C) 6 g (D) 3 g
8. What will be the gram atomic weight of Mg, if 24 g of 12
Mg24
contains 6.023 × 1023
atoms ?
(A) 12 g (B) 36 g (C) 24 g (D) 48 g
9. Compute gram molecular weight of H2
gas if 4 g of H2
gas contains 24.09 × 1023
atoms :
(A) 4 g (B) 3 g (C) 2 g (D) 1 g

PAGE NO. # 2
10. Fill the blanks in the table. Where NA
is Avogadro number.
Sample
Relative atomic
Mass for the
element
Gram
Atomic
mass of
sample
Moles of
sample
No. of atoms
of sample
Mass removed
from the sample
Mole
removed
atoms
removed
Mass of same no.
of C atom as No. of
atoms present in
the original sample
8 gm O atom 16 _ _ _ _ _ _ _ _ _ 2 gm _ _ _ _ _ _ _ _ _
For Example 16 16 gm ½ mole 2 gm mole 6 gm
230 gm Na 23 46 gm
60 gm Ca 40 1 mole
20 gm He 4 3 mole
56 gm N 14 ½ mole
12 gm Mg 24
128 gm S 32 NA
93 gm P 31
4
NA
2
N3 A
2
NA
8
NA
8
1
DPP No. # 2
1. According to common practice, if you have Avogadro number of Hydrogen then its mass is equal to :
(A) 1 g (B) 2 g (C) 4 g (D) depends on temperature
2. From 64 g oxygen, 11.2 lit. Oxygen gas at S.T.P and 6.02 × 1023
oxygen atoms are removed from the
oxygen container. Find the mass of the oxygen gas left.
(A) zero (B) 32 g (C) 16 g (D) none
3. From the mixture of 4 moles Ca3
(PO4
)2
and 5 moles of P4
O10
and 6 moles of H3
PO3
all the phosphorus
atoms are removed then moles of P4
molecule formed from all these atoms is :
(A) 8.5 (B) 17 (C) 34 (D) 10
4. If a sample of CuSO4
.5H2
O contains 3 moles of oxygen molecule the mole of H-atoms present in the sample is:
(A) 5 (B) 9 (C) 10/3 (D) 20/3
5. Sulphur exist in different allotropic forms like S2
, S6
and S8
etc. If equal weight of three are taken in
separate container then the ratio of number of atoms is :
(A) 1 : 3 : 4 (B) 1 : 1 : 1 (C) 2 : 4 : 3 (D) 1 : 1 : 4
6. Which of the following contains the greatest number of atoms ?
(A) 1.0 g of butane (C4
H10
) (B) 1.0 g of nitrogen (N2
)
(C) 1.0 g of silver (Ag) (D) 1.0 g of water (H2
O)
7. Under the same conditions, two gases have the same number of molecules. They must :
(A) be noble gases. (B) have equal volumes.
(C) have a volume of 22.4 dm3
each. (D) have an equal number of atoms.
8. Agaseous mixture contains CO2
(g) and N2
O(g) in a 2 : 5 ratio by mass. The ratio of the number of molecules
of CO2
(g) and N2
O(g) is :
(A) 5 :2 (B) 2 : 5 (C) 1 : 2 (D) 5 : 4
9. In which of the following pairs do 1 g of each have an equal number of molecules?
(A) N2
O and CO (B) N2
and C3
O2
(C) N2
and CO (D) N2
O and CO2
10. 11.2 L of a gas at STP weights 14.0 g. The gas could be :
(A) N2
O (B) NO2
(C) N2
(D) CO

PAGE NO. # 3
DPP No. # 3
1. The atomic weight for a triatomic gas is a. The correct formula for the number of moles of gas in its w g is:
(A)
a
w3
(B)
a3
w
(C) 3wa (D)
w3
a
2. 16 g of SOx
occupies 5.6 litre at S.T.P. Assuming ideal gas nature, the value of x is :
(A) 1 (B) 2 (C) 3 (D) none of these
3. Find the relative density of SO3
gas with respect to methane.
4. Vapour density of a gas is 17 then find the weight of 11.2 L. of gas at STP.
5. Compounds of boron with hydrogen are called boranes. One of these boranes has the empirical formula
BH3
and a molecular weight of 28 amu. What is its molecular formula ?
6. Calculate vapour density of a sample containing 10 moles of CO2, 5 moles of SO2 & 400 g of SO3 with
respect to CH4 gas.
7. Calculate total number of carbon atoms in a sample containing 160 g of CH4, 600 g of acetic acid, 340 g of
C3O2 & 360 g of pentane.
8. Match the following :
Column - I Column - II
(A) 49 g H2
SO4
(p) 0.5 mole
(B) 20 g NaOH (q) 1.5 NA
atoms
(C) 11.2 L of CO2
at STP (r) 0.5 NA
molecules
(D) 6.023 × 1023
atoms of Oxygen (s) 2 mole of ‘O’ atom
9. Column - I Column - II
(A) 32 gm each of O2 and S (p) 2 moles of Fe
(B) 2 gram molecule of K3[Fe(CN)6] (q) 3 moles of ozone molecule
(C) 144 gm of oxygen atom (r) one mole
(D) From 168 g of iron 6.023 × 1023 atoms (s) 12 moles of carbon atoms
of iron are removed the iron left
DPP No. # 4
1. An element (A) (at wt = 75) and another element (B) (at. wt. = 25) combine to form a compound. The
compound contains 75% (A) by weight. The formula of the compound will be -
(A) A2B (B) A3B (C) AB3 (D) AB
2. The empirical formula of a compound is CH. Its molecular weight is 78. The molecular formula of the
compound will be -
(A) C2H2 (B) C3H3 (C) C4H4 (D) C6H6
3. Hydrogen and oxygen combine to form H2O2 and H2O containing 5.93% and 11.2% Hydrogen
respectively. The data illustrates-
(A) Law of conservation of mass (B) Law of constant proportions
(C) Law of reciprocal proportions (D) Law of multiple proportions

PAGE NO. # 4
4. If water samples are taken from sea, rivers, clouds, lake or snow, they will be found to contain H2
and O2 in the fixed ratio of 1 : 8. This indicates the law of -
(A) Multiple proportion (B) Definite proportion
(C) Reciprocal proportion (D) None of these.
5. 1.2 gm of Mg (At. mass 24) will produce MgO equal to -
(A) 0.05 mol (B) 40 gm (C) 40 mg (D) 4 gm
6. One of the following combinations illustrate law of reciprocal proportions-
(A) N2O3, N2O4, N2O5 (B) NaCl, NaBr, NaI (C) CS2, CO2, SO2 (D) PH3, P2O3, P2O5
7. The law of multiple proportions is illustrated by -
(A) Carbon monoxide and carbon dioxide (B) Potassium bromide and potassium chloride
(C) Water and heavy water (D) Calcium hydroxide and barium hydroxide.
8. Column matching :
Column I Column II
(A) CaC2 (p) 106 gm
(B) 2 g-equivalent of Na2CO3 (q) 22.4 L at S.T.P.
(C) 6.02 × 1023
Ne atoms (r) N0 formula units
(D) Mohr’s salt (s) Calcium carbide
(E) Contain 18 gm-atom of N (t) (NH4)2SO4.Fe(SO4).6H2O
ANSWER KEY
DPP No. # 1
1. (C) 2. (D) 3. (C) 4. (B) 5. (A) 6. (D) 7. (B)
8. (C) 9. (C)
DPP No. # 2
1. (A) 2. (B) 3. (A) 4. (D) 5. (A) 6. (A) 7. (B)
8. (B) 9. (D) 10. (C)
DPP No. # 3
1. (B) 2. (B) 3. 5 4. 17 5. B2
H6
6.
58
16
7. 70NA
8. (A) p,r,s (B) p,r (C) p, q, r (D) r 9. (A) p,r (B) p,s (C) q (D) p
DPP No. # 4
1. (D) 2. (D) 3. (D) 4. (B) 5. (A) 6. (C) 7. (A)
8. (A) s (B) p (C) q; (D) (t) (E) t

PAGE NO. # 1
CHEMISTRY
D P P
TARGET
DPP No. # 05
1. The chloride of a metal contains 71% chlorine by weight and the vapour density of it is 50. The atomic
weight of the metal will be -
(A) 29 (B) 58 (C) 35.5 (D) 71
2. The haemoglobin of most mammals contains approximately 0.33% of iron by mass. The molecular
mass of haemoglobin is 67200. The number of iron atoms in each molecule of haemoglobin is-
(A) 3 (B) 4 (C) 2 (D) 6
3. The formula which represents the simple ratio of atoms in a compound is called -
(A) molecular formula (B) structural formula (C) empirical formula (D) rational formula
4. On analysis, a certain compound was found to contain 254 gm of iodine (at. mass 127) and 80 gm
oxygen (at. mass 16). What is the formula of the compound -
(A) IO (B) I2O (C) I5O3 (D) I2O5
5. 14g of element X combine with 16g of oxygen. On the basis of this information, which of the following
is a correct statement :
(A) The element X could have an atomic weight of 7 and its oxide formula XO
(B) The element X could have an atomic weight of 14 and its oxide the formula X2O
(C) The element X could have an atomic weight of 7 and its oxide is X2O
(D) The element X could have an atomic weight of 14 and its oxide is XO2
6. The law of conservation of mass holds good for all of the following except -
(A) All chemical reactions (B) Nuclear reactions
(C) Endothermic reactions. (D) Exothermic reactions.
Passage (Q. No. 7 to 9)
10 moles of SO2 and 4 moles of O2 are mixed in a closed vessel of volume 2 litres. The mixture
is heated in presence of Pt catalyst. Following reaction takes place :
2SO2(g) + O2(g)  2SO3(g)
Assuming the reaction proceeds to completion.
7. Select the correct statement -
(A) SO2 is the limiting reagent (B) O2 is the limiting reagent
(C) both SO2 and O2 are limiting reagent (D) cannot be predicted
8. Number of moles of SO3 formed in the reaction will be -
(A) 10 (B) 4 (C) 8 (D) 14
9. Number of moles of excess reactant remaining -
(A) 4 (B) 2 (C) 6 (D) 8

PAGE NO. # 2
DPP No. # 06
Fill in the blank :
1. For the reaction,
2x + 3y + 4z  5w
Initially if 1 mole of x, 3 mole of y and 4 mole of z is taken. If 1.25 mole of w is obtained then % yield of this
reaction is _______.
2. The vapour density of a mixture of gas A (Molecular mass = 40) and gas B (Molecular mass = 80) is 25.
Then mole % of gas B in the mixture would be ________.
3. For the reaction
2A + 3B + 5C  3D
Initially if 2 mole of A, 4 mole of B and 6 mole of C is taken. With 25% yield, moles of D which can be
produced are _________.
Single Correct:
4. Mass of sucrose C12H22O11 produced by mixing 84 gm of carbon, 12 gm of hydrogen and
56 lit. O2 at 1 atm & 273 K according to given reaction, is
C(s) + H2(g) + O2 (g)  C12H22O11(s)
(A) 138.5 (B) 155.5 (C) 172.5 (D) 199.5
5. The percentage by mole of NO2 in a mixture of NO2(g) and NO(g) having average molecular mass 34 is :
(A) 25% (B) 20% (C) 40% (D) 75%
6. The minimum mass of mixture of A2 and B4 required to produce at least 1 kg of each product is :
(Given At. mass of 'A' = 10 ; At. mass of 'B' = 120)
5A2 + 2B4  2AB2 + 4A2B
(A) 2120 gm (B) 1060 gm (C) 560 gm (D) 1660 gm
7. 74 gm of a sample on complete combustion gives 132 gm CO2 and 54 gm of H2O. The molecular formula
of the compound may be :
(A) C5H12 (B) C4H10O (C) C3H6O2 (D) C3H7O2
8. An iodized salt contains 0.5 % of NaI. Aperson consumes 3 gm of salt everyday. The number of iodide ions
going into his body everyday is :
(A) 10–4 (B) 6.02 ×10–4 (C) 6.02 × 1019 (D) 6.02 × 1023
9. The mass of Mg3N2 produced if 48 gm of Mg metal is reacted with 34 gm NH3 gas is :
Mg + NH3  Mg3N2 + H2
(A)
3
200
(B)
3
100
(C)
3
400
(D)
3
150

PAGE NO. # 3
DPP No. # 07
1. The mass of P4O10 produced if 440 gm of P4S3 is mixed with 384 gm of O2 is :
P4S3 + O2  P4O10 + SO2
(A) 568 gm (B) 426 gm (C) 284 gm (D) 396 gm
2. Calculate percentage change in Mavg of the mixture, if PCl5 undergo 50% decomposition.
PCl5  PCl3 + Cl2
(A) 50% (B) 66.66 % (C) 33.33 % (D)Zero'kwU;
3. Statement -1 : 2A + 3B  C
4/3 moles of 'C' are always produced when 3 moles of 'A' & 4 moles of 'B' are added.
Statement -2 : 'B' is the liming reactant for the given data.
(A) Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement-1.
(B) Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement-1.
(C) Statement-1 is false, statement-2 is true.
(D) Statement-1 is true, statement-2 is false.
4. The recommended daily dose is 17.6 milligrams of vitamin C (ascorbic acid) having formula C6H8O6.
Match the following. Given : NA = 6 × 1023
Column I Column II
(A) O-atoms present (p) 10–4 mole
(B) Moles of vitamin C in 1 gm of vitamin C (q) 5.68 × 10–3
(C) Moles of vitamin C in 1 gm should be consumed daily (r) 3.6 × 1020
5. The number of carbon atoms present in a signature, if a signature written by carbon pencil weights
1.2 × 10–3 g is :
(A) 12.04 × 1020 (B) 6.02 × 1019 (C) 3.01 × 1019 (D) 6.02 × 1020
6. The average atomic mass of a mixture containing 79 mole % of 24Mg and remaining 21 mole % of 25Mg
and 26Mg , is 24.31. % mole of 26Mg is :
(A) 5 (B) 20 (C) 10 (D) 15
7. The density of a liquid is 1.2 g/mL. There are 35 drops in 2 mL. The number of molecules in one drop
(molar mass of liquid = 70 g/mol) is :
(A) A
1.2
N
35
 
 
 
(B)
2
A
1.2 1
N
35 35
 
 
 
(C) A3
1.2
N
(35) (D) 1.2 NA
8. Sulphur trixoide is prepared by the following two reactions
S8(s) + 8 O2(g)  8 SO2(g) ; 2SO2(g) + O2(g)  2SO3(g)
How many grams of SO3 are produced from 1 mol of S8?
(A) 1280.0 (B) 640.0 (C) 960.0 (D) 320.0
9. A compound of Mg contains 6% of Mg then find the minimum molar mass of compound.

PAGE NO. # 4
DPP No. # 08
1. Vapour density of equimolar mixture of CH4, O2 and SO2 is :
(A) 18.67 (B) 16 (C) 36 (D) 37.3
2. If law of conservation of mass was to hold true, then 20.8 gm of BaCl2 on reaction with 9.8 gm of
H2SO4 will produce 7.3 gm of HCl and BaSO4 equal to -
(A) 11.65 gm (B) 23.3 gm (C) 25.5 gm (D) 30.6 gm
3. A sample contains 9.81 g Zn, 1.8 × 1023 atoms of Cr and 0.6 g-atoms of O. What is empirical formula of
compound ? (Zn = 65 g/mol)
4. If 240 g of carbon is taken in a container to convet it completely to CO2 but in industry it has been found that
280 g of CO was also formed along with CO2. Find the percentage yield of CO2. The reaction occurring are
C + O2  CO2 ; C +
1
2
O2 CO
(A) 25% (B) 50% (C) 75% (D) 100%
5. 100 g impure CaCO3 on heating gives 5.6 lit. CO2 gas at STP. Find the percentage of calcium in the lime
stone sample. [At wt. : Ca = 40 ; C = 12 ; O = 16]
(A) 10 (B) 20 (C) 1 (D) 30
Match the column
6. One type of artifical diamond (commonly called YAG for yttrium aluminium garnet) can be represented by
the formula Y3Al5O12.[Y = 89, Al =27]
Column I Column II
Element Weight percentage
(A) Y (p) 22.73%
(B) Al (q) 32.32%
(C) O (r) 44.95%
7. Butane, C4H10, burns with the oxygen in air to give carbon dioxide and water.
What is the amount (in moles) of carbon dioxide produced from 0.15 mole C4H10?
C4H10(g) + O2(g)  CO2(g) + H2O(g) (not balanced)
Answer Key
DPP No. # 5
1. (A) 2. (B) 3. (C) 4. (D) 5. (C) 6. (B) 7. (B)
8. (C) 9. (B)
DPP No. # 06
1. 50% 2. 25% 3. 0.75 4. (B) 5. (A) 6. (A) 7. (C)
8. (C) 9. (A)
DPP No. # 07
1. (B) 2. (C) 3. (C) 4. (A) r, (B) q, (C) p 5. (B) 6. (C)
7. (C) 8. (B) 9. 400 g/mole
DPP No. # 08
1. (A) 2. (B) 3. ZnCr2O4 4. (B) 5. (A)
6. (A) r, (B) p, (C) q
7. 0.6

PAGE NO. # 1
CHEMISTRY
D P P
TARGET
DPP No. # 09
1. 84 g of iron (Fe) is reacted with sufficient amount of steam to produced 44.8 lit., H2 gas at S.T.P.
according the following reaction, a Fe + b H2O c Fe3O4 + d H2. The stoichiometric coefficients
of the reaction is (Atomic wt. : Fe = 56, O = 16, H = 1)
(A) 4, 3, 1, 4 (B) 3, 4, 1, 4 (C) 1, 4, 2, 3 (D) None of these
2. If 240 g of carbon is taken in a container to convert it completely to CO2 but in industry it has been
found that 280 g of CO was also formed along with CO2. Find the percentage yield of CO2. The
reactions occuring are :
C + O2  CO2 ; C +
1
2
O2  CO
(A) 25% (B) 50% (C) 75% (D) 100%
3. 120 g Mg was burnt in air to give a mixture of MgO and Mg3N2. The mixture is now dissolved in HCl
to form MgCl2 and NH4Cl, if 107 grams NH4Cl is produced. Then the moles of MgCl2 formed is:
(Atomic wt. : Mg = 24, N = 14, Cl = 35.5)]
(A) 3 moles (B) 6 moles (C) 5 moles (D) 10 moles
4. 100 g impure CaCO3 on heating gives 5.6 litre CO2 gas at STP. Find the percentage of calcium in
the lime stone sample. [Atomic weight : Ca = 40; C = 12 : O = 16]
(A) 10 (B) 20 (C) 1 (D) 30
5. 75 mL of H2SO4 (specific gravity = 1.18) containing 49% H2SO4 by mass is diluted to 590 mL.
Calculate molarity of the diluted solution. [S = 32]
(A) 0.7 M (B) 7.5 M (C) 0.75 M (D) 0.25 M
6. Calculte the molarity when :
(a) 4.9 g H2SO4 acid dissolved in water to result 500 mL solution
(b) 2 gram molecule of KOH dissolved in water to result 500 mL solution
7. How would you prepare exactly 3 litre of 1.0 M NaOH by mixing proportions of stock solution of
2.5 M NaOH and 0.4 M NaOH if no water is to be used. Find the ratio of the volume (v1/v2).
8. What volume of 0.25 M HNO3 (nitric acid) reacts with 50 mL of 0.15 M Na2CO3 (sodium carbonate)
in the following reaction?
2HNO3 (aq) + Na2CO3(aq)  2NaNO3 (aq) + H2O() + CO2(g)

PAGE NO. # 2
9. Zinc and hydrochloric acid react according to the reaction :
Zn(s) + 2HCl (aq)  ZnCl2(aq) + H2(g)
If 0.30 mole of Zn are added to hydrochloric acid containing 0.52 mole HCl, how many moles of H2
are produced :
10. Match the following :
Column-I Column-II
For 1 mole of reactant placed in Product
open container in each reaction
(A) PCl5 (g) 
 PCl3 (g) + Cl2(g) (p) 2NA molecules
(B) CaCO3(s) 
 CaO(s) + CO2(g) (q) 67.2 litre gaseous product at STP
(C) 2HCl (g) 
 H2(g) + Cl2(g) (q) 22.4 litre gaseous product at STP
(D) NH4COONH2(s) 
 2NH3(g) + CO2(g) (s) 44.8 litre gaseous product at STP
DPP No. # 10
1. What volume of a 0.8 M solution contains 100 millimoles of the solute?
(A) 100 mL (B) 125 mL (C) 500 mL (D) 62.5 mL
2. Calculate the volume in litre of 1 M solution of HCl which contain 36.5 g HCl?
3. The molarity of the KOH solution which is containing 2.8% mass-volume solution of KOH is :
(A) M/10 (B) M/2 (C) M/5 (D) 1 M
4. 75 mL of H2SO4 (specific gravity = 1.18) containing 49% H2SO4 by mass is diluted to 590 mL.
Calculate molarity of the diluted solution. [S = 32]
(A) 0.7 M (B) 7.5 M (C) 0.75 M (D) 0.25 M
5*. If 100 mL of 1 M H2SO4 solution is mixed with 100 mL of 9.8% (w/w/) H2SO4 solution (d = 1 gm/
mL) then :
(A) concentration of solution remains same (B) volume of solution become 200 mL
(C) mass of H2SO4 in the solution is 98 gm (D) mass of H2SO4 in the solution is 19.6 gm
6*. For 100 mL of 0.2 M AlCl3 solution + 400 mL of 0.1 M HCl solution correct datas are :
(A) Total concentration of cation (s) = 0.12 M
(B) Total concentration of cation(s) = 0.06 M
(C) [Cl–] = 0.1 M
(D) [Cl–] = 0.2 M

PAGE NO. # 3
Comprehension :
Read the following comprehension carefully and answer the questions (Q. 7 to Q. 10)
The concentrations of solutions can be expressed in number of ways ; viz : mass fraction of solute
(or mass percent), Molar concentration (Molarity) and Molal concentration (molality). These terms are
known as concentration terms and also they are related with each other i.e. knowing one concentration
term for the solution, we can find other concentration terms also. The definition of different concentration
terms are given below :
Molarity : It is number of moles of solute present in one litre of the solution.
Molality : It is the number of moles of solute present in one kg of the solvent
Mole fraction =
moles of solute
moles of solute + moles of solvent
If molality of the solution is given as 'a' then mole fraction of the solute can be calculated by
Mole fraction =
solvent
solvent
solvent
a Ma
1000 (a M 1000)
a+
M


  where a = molality and Msolvent = Molar mass of
solvent
We can change : Mole fraction  Molality  Molarity.
7. 120 g of solution containing 40% by mass of NaCl are mixed with 200 g of a solution containing 15%
by mass NaCl. Determine the mass percent of sodium chloride in the final solution :
(A) 24.4% (B) 78% (C) 48.8% (D) 19.68%
8. What is the molality of the above solution ?
(A) 4.4 m (B) 5.5 m (C) 24.4 m (D) None
9. What is the mole fraction of the solute :
(A) 0.18 (B) 0.75 (C) 0.09 (D) 0.25
10. What is the molarity of solution if density of solution in 1.6 g/mL ?
(A) 5.5 M (B) 6.6 M (C) 2.59 M (D) None
ANSWER KEY
DPP No. # 09
1. (B) 2. (B) 3. (C) 4. (A) 5. (C)
6. (a) 0.1 M (b) 4 M 7. 2 : 5 8. 60 mL 9. 0.26
10. (A) p,s (B) p, r (C) r (D) q
DPP No. # 10
1. (B) 2. 1 3. (B) 4. (C) 5*. (ABD)
6*. (AD) 7. (A) 8. (B) 9. (C) 10. (B)

Dpp 02 mole_concept_jh_sir-3572

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Dpp 02 mole_concept_jh_sir-3572