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KEY
Chemistry: Stoichiometry – Problem Sheet 2
Directions : Solve each of the following problems. Show your work, including proper units, to earn full credit.
- ___ CaCl 2 + ___ AgNO 3 ___ Ca(NO 3 ) 2 + ___ AgCl
How many grams of silver chloride are produced when 45 g of calcium chloride react with excess silver nitrate? 116 gAgCl 1 molAgCl
- 5 gAgCl 1 molCaCl
2 molAgCl 111 gCaCl
1 molCaCl xgAgCl 45 gCaCl 2 2
2 2
- ___ CuO + ___ H 2 ___ Cu + ___ H 2 O
At STP, how many liters of hydrogen are needed to react with 88 g of copper (II) oxide?
2 2
2 2 (^2 1) molH 24.8LH
22.4LH
1 molCuO
1 molH 79.5gCuO
xLH 88 gCuO^1 molCuO
- ___ Na + ___ H 2 O ___ NaOH + ___ H 2
If 3 liters of hydrogen (at STP) are produced in the above reaction, what mass of sodium was used? 6.2gNa 1 molNa
23 gNa 1 molH
2 molNa 22.4LH
1 molH xgNa 3 LH 2 2
2 2
4. ___ CH 4 + ___ O 2 ___ CO 2 + ___ H 2 O
What volume of methane is needed to completely react with 500 liters of oxygen?
4 4
4 2
4 2
2 (^4 21) molCH^250 LCH
22.4LCH
2 molO
1 molCH 22.4LO
xLCH 500 LO^1 molO
5. ___ CS 2 + ___ O 2 ___ CO 2 + ___ SO 2
How many molecules of carbon disulfide will react with 4.21 x 10^19 molecules of oxygen?
(^192) 2
(^232) 2
2 (^232) 2 19 2 2 1.40x10 moleculesCS 1 molCS
6.02x10 moleculesCS 3 molO
1 molCS 6.02x10 moleculesO xmoleculesCS 4.21x10 moleculesO^1 molO
6. ___ C 2 H 6 ___ C 2 H 4 + ___ H 2
If 5.76 x 10^28 molecules of ethane are broken down, what volume of hydrogen gas is produces at STP?
2 6 2
2 2 6
2 2 6 23
2 6 2 6 28 (^2 1) molH 2.14x10 LH
22.4LH
1 molCH
1 molH 6.02x10 moleculesCH
xLH 5.76x10 moleculesCH^1 molCH
- ___ Fe + ___ H 2 O ___ Fe 3 O 4 + ___ H 2
If 67.8 dm^3 of hydrogen are produced at STP, how many atoms of iron were used in the reaction?
1.37x10 atomsFe 1 molFe
6.02x10 atomsFe 4 molH
3 molFe 22.4dm H
1 molH x atomsFe 67.8dm H^24
23 (^322)
(^322)
- ___ KClO 3 ___ KCl + ___ O 2
If 8.65 x 10^25 molecules of potassium chloride are produced, what mass of oxygen is produced?
2 2
2 2 23
25 (^2 1) molO^6897 gO
32 gO 2 molKCl
3 molO 6.02 10 moleculesKCl
xgO 8.65 10 moleculesKCl^1 molKCl
- ___ NaI + ___ Cl 2 ___ NaCl + ___ I 2
How many molecules of iodine are liberated if 546 g of chlorine react with excess sodium iodide?
2 24 2
2 23
2
2 2
2 (^2 21) molI^4 .63x^10 moleculesI
6 .02x 10 moleculesI 1 molCl
1 molI 71 gCl
xmoleculesI 546 gCl^1 molCl
- ___ Cu + ___ AgNO 3 ___ Cu(NO 3 ) 2 + ___ Ag
How many grams of silver will be produced if 86 g of copper are used? 292 gAg 1 molAg
108 gAg 1 molCu
1 molAg 63.5gCu
x gAg 86 gCuO^1 molCu
- ___ (NH 4 ) 2 SO 4 + ___ Ca(OH) 2 ___ CaSO 4 + ___ NH 3 + ___ H 2 O
At STP, how many dm^3 of ammonia are produced by using 26.0 g of calcium hydroxide?
3 3 3
3 3
2
3 2
2 (^3 21) molNH 15.7dm NH
22.4dm NH 1 molCa(OH)
2 molNH 74 gCa(OH)
xLNH 26.0gCa(OH)^1 molCa(OH)
- ___ NaCl + ___ H 2 SO 4 ___ HCl + ___ Na 2 SO 4
If 359 g of sodium chloride are consumed in the reaction, how many molecules of sodium sulfate are produced?
2 4 2 4 23 2 4
2 4 23 (^2 41) molNaSO 1.85x^10 moleculesNaSO
6.02x 10 moleculesNaSO 2 molNaCl
1 molNaSO 58.5gNaCl xmoleculesNaSO 395 gNaCl^1 molNaCl
- ___ AgCH 3 COO + ___ Na 3 PO 4 ___ Ag 3 PO 4 + ___ NaCH 3 COO
What mass of AgCH 3 COO will react with 4.77 x 10^26 molecules of sodium phosphate?
3 mol 1 molAgCHNaPOCOO 1167 molgAgCHAgCHCOOCOO 3.97x 10 gAgCHCOO 6.02x10 moleculesNaPO x gAgCHCOO 4.77x10 moleculesNaPO^1 molNaPO 33 4 33 5 3 (^2334) 3 26 3 4 3 4
- ___ HgO ___ Hg + ___ O 2
What mass of mercury (II) oxide is required to produce 812 liters of oxygen (at STP)? 1.57x 10 gHgO 1 molHgO
216.6gHgO 1 molO
2 molHgO 22.4LO
1 molO x gHgO 812 LO^4 2 2
2 2
- ___ Ag 2 O ___ Ag + ___ O 2
How many molecules of silver oxide are needed to produce 445 dm^3 of oxygen (at STP)? 2.39x10 moleculesAgO 1 molAgO
6.02x10 moleculesAgO 1 molO
2 molAgO 22.4dm O
x moleculesAgO 445 dm O^1 molO (^252) 2
(^232) 2
2 (^32) 2 3 2 2
- ___ Al + ___ HCl ___ AlCl 3 + ___ H 2
How many liters of hydrogen (at STP) are produced by reacting 3.54 x 10^24 atoms of aluminum with excess hydrochloric acid?
2 2
2 2 23
24 (^2 1) molH^198 LH
2 2.4LH
2 molAl
3 molH 6.02 10 atomsAl
xLH 3.54 10 atomsAl^1 molAl
Answers: 1. 116 g AgCl 5. 1.40 x 10^19 molecules CS 2 9. 4.63 x 10^24 molecules I 2 13. 3.97 x 10^5 g AgCH 3 COO
- 24.8 L H 2 6. 2.14 x 10^6 L H 2 10. 292 g Ag 14. 1.57 x 10^4 g HgO
- 6.2 g Na 7. 1.37 x 10^24 atoms Fe 11. 15.7 dm^3 NH 3 15. 2.39 x 10^25 molecules Ag 2 O
- 250 L CH 4 8. 6897 g O 2 12. 1.85 x 10^24 molecules 16. 198 L H 2
Chemistry: Stoichiometry – Problem Sheet 2 KEY
9)^242
2
2 23 2
2 2
2 2 2 4 .63x^10 moleculesI 1 molI
6 .02x 10 moleculesI 1 molCl
1 molI 71 gCl
1 molCl xmoleculesI 546 gCl
10) 292 gAg
1 molAg
108 gAg 1 molCu
1 molAg 63.5gCu
1 molCu xgAg 86 gCuO
11)^33
3
3 3
2
3 2
2 (^3 21) molNH 15.7dm NH
22.4dm NH 1 molCa(OH)
2 molNH 74 gCa(OH)
xLNH 26.0gCa(OH)^1 molCa(OH)
23 2 4
2 4 23 2 4 2 4 1.85x^10 molecules 1 molNa SO
6.02x 10 moleculesNa SO 2 molNaCl
1 molNa SO 58.5gNaCl
1 molNaCl xmoleculesNaSO 395 gNaCl
1 molAgCHCOO
167 gAgCHCOO 1 molNaPO
3 molAgCH COO 6.02x10 moleculesNa PO
xgAgCHCOO 4.77x10 moleculesNaPO^1 molNa PO 3
3 3 4
3 3 4 23
3 4 3 4 26 3
14) 1.57x 10 gHgO
1 molHgO
216.6gHgO 1 molO
2 molHgO 22.4LO
x gHgO 812 LO^1 molO^4 2 2
2 2
2.39x10 moleculesAgO 1 molAgO
6.02x10 moleculesAgO 1 molO
2 molAgO 22.4dm O
x moleculesAgO 445 dm O^1 molO 2 25 2
(^232) 2
2 2 3
2 2 3 2
2
2 2 23
24 (^2 1) molH^198 LH
2 2.4LH
2 molAl
3 molH 6.02 10 atomsAl
xLH 3.54 10 atomsAl^1 molAl
