180
Stoichlometry II Calculations Based on Chemical Equations
2 Some common gases may be prepared in the laboratory using reactions represented by the following balanced equations A A sign indicates that heating
is necessary For purity, air must be swept out of the apparatus before the gas
is collected, and some gases must be dried with a suitable desiccant
FeS + 2HC1 -> H 2 S + FeCl 2
CaCO 3 + 2HC1 -^ CO 2 + CaCl 2 + H 2 O
2NH 4 Cl + CaO -4 2NH 3 + CaCl 2 + H 2 O
NaCl + H 2 SO 4 -4 HCl + NaHSO 4
NH 4 Cl + NaNO 3 -4 N 2 O + NaCl + 2H 2 O
2Al + 3H 2 SO 4 -^ Al^SOJa + 3H 2
CaC 2 + 2H 2 O -H> C 2 H 2 + Ca(OH) 2
(a) What weight of FeS is needed to prepare (i) 4 50 moles of H 2 S
9 (//) I 00 Ib
of H 2 S
9
(b) How many tons of limestone (CaCO,) are needed to prepare 5 00 tons of
dry ice (CO 2 ), assuming that 30% of the CO 2 produced is wasted in
converting it to the solid
9
(c) How many grams of NH 4 C1 and CaO are needed to make 0 100 mole of
NH 3
9
(d) How many grams of 95% pure NaCl are needed to produce 2 00 Ib of HCl
9
(e) What volume of commercial HCl (36% HCl by weight, density = 1 18g/ml)
and what weight of limestone (90% pure) are needed to produce 2 00 kg of
CO 2
9
(f) Commercial sulfunc acid that has a density of 1 84 g/ml and is 95% H 2 SO 4
by weight is used for the production of HCl
(/) What weight of commercial acid is needed for the production of 365 g of HCl
9
(i<) What
volume of acid is needed for the production of 365 g of HCl
9
(g) Commercial sulfunc acid that has a density of 1 45 g/ml and is 55 1%
H 2 SO 4 by weight is used for the production of H 2 What (i) weight and (n)
volume of this commercial acid are needed for the production of 50 0 g of
H 2 gas
9
(h) A manufacturer supplies 1 Ib cans of calcium carbide whose purity is
labeled as 85% How many grams of acetylene can be prepared from 1 00
Ib of this product if the label is correct
9
(i) A whipped cream manufacturer wishes to produce 500 Ib of N 2 O for her
chain of soda fountains What is the cost of the necessary NH 4 C1 and
NaNO 3 if they cost $840 and $1230 per ton, respectively
9
0) A 0 795 g sample of impure limestone is tested for purity by adding H 2 SO 4
(instead of HCl as shown in the second equation) After the generated gas
is passed over Mg(ClO 4 ) 2 to dry it, it is passed over soda lime (a mixture of
sodium and calcium hydroxides), which absorbs the CO 2 The soda-lime
tube increases in weight by 0 301 g What is the percentage of CaCO 3 in
the original sample
9
(k) The purity of a 0 617 g sample of impure FeS is tested by passing the H 2 S
produced by the HCl (as in the first equation) into a dilute solution of
AgNO 3 The precipitate of Ag 2 S is filtered off, washed, and gently dned
Stoichlometry II Calculations Based on Chemical Equations
2 Some common gases may be prepared in the laboratory using reactions represented by the following balanced equations A A sign indicates that heating
is necessary For purity, air must be swept out of the apparatus before the gas
is collected, and some gases must be dried with a suitable desiccant
FeS + 2HC1 -> H 2 S + FeCl 2
CaCO 3 + 2HC1 -^ CO 2 + CaCl 2 + H 2 O
2NH 4 Cl + CaO -4 2NH 3 + CaCl 2 + H 2 O
NaCl + H 2 SO 4 -4 HCl + NaHSO 4
NH 4 Cl + NaNO 3 -4 N 2 O + NaCl + 2H 2 O
2Al + 3H 2 SO 4 -^ Al^SOJa + 3H 2
CaC 2 + 2H 2 O -H> C 2 H 2 + Ca(OH) 2
(a) What weight of FeS is needed to prepare (i) 4 50 moles of H 2 S
9 (//) I 00 Ib
of H 2 S
9
(b) How many tons of limestone (CaCO,) are needed to prepare 5 00 tons of
dry ice (CO 2 ), assuming that 30% of the CO 2 produced is wasted in
converting it to the solid
9
(c) How many grams of NH 4 C1 and CaO are needed to make 0 100 mole of
NH 3
9
(d) How many grams of 95% pure NaCl are needed to produce 2 00 Ib of HCl
9
(e) What volume of commercial HCl (36% HCl by weight, density = 1 18g/ml)
and what weight of limestone (90% pure) are needed to produce 2 00 kg of
CO 2
9
(f) Commercial sulfunc acid that has a density of 1 84 g/ml and is 95% H 2 SO 4
by weight is used for the production of HCl
(/) What weight of commercial acid is needed for the production of 365 g of HCl
9
(i<) What
volume of acid is needed for the production of 365 g of HCl
9
(g) Commercial sulfunc acid that has a density of 1 45 g/ml and is 55 1%
H 2 SO 4 by weight is used for the production of H 2 What (i) weight and (n)
volume of this commercial acid are needed for the production of 50 0 g of
H 2 gas
9
(h) A manufacturer supplies 1 Ib cans of calcium carbide whose purity is
labeled as 85% How many grams of acetylene can be prepared from 1 00
Ib of this product if the label is correct
9
(i) A whipped cream manufacturer wishes to produce 500 Ib of N 2 O for her
chain of soda fountains What is the cost of the necessary NH 4 C1 and
NaNO 3 if they cost $840 and $1230 per ton, respectively
9
0) A 0 795 g sample of impure limestone is tested for purity by adding H 2 SO 4
(instead of HCl as shown in the second equation) After the generated gas
is passed over Mg(ClO 4 ) 2 to dry it, it is passed over soda lime (a mixture of
sodium and calcium hydroxides), which absorbs the CO 2 The soda-lime
tube increases in weight by 0 301 g What is the percentage of CaCO 3 in
the original sample
9
(k) The purity of a 0 617 g sample of impure FeS is tested by passing the H 2 S
produced by the HCl (as in the first equation) into a dilute solution of
AgNO 3 The precipitate of Ag 2 S is filtered off, washed, and gently dned