Gas Law problems with solution Part - 4

16. A 250 Kg tank of liquid butane (C4H1O) burns to produce carbon dioxide at 120°C. What volume of carbon dioxide is produced at 1 Atm?


17. How many liters of product at 950 mmHg and O°C is produced by the burning of three liters of acetylene (C2H2) at 5 atm and 20°C?

18. Five grams of octane (C8H18) and enough oxygen to burn it are in an automobile cylinder compressed to 20 atm at 28°C. The mixture explodes and heats the cylinder to 150°C. What is the pressure in the (same sized) cylinder after the explosion?

19. If 0.515g of magnesium is added to HCl, it makes hydrogen gas and magnesium chloride. The hydrogen is collected at 23°C and 735mmHg. What is the volume of hydrogen?

20. What is the mass of 150 liters of propane gas (C3H8) at 37°C and 245 inHg?

21. Isopropyl alcohol, C3H7OH, makes a good fuel for cars. What volume of oxygen at 735 mmHg and 23°C is needed to burn one kilogram of isopropyl alcohol?

22. What volume does 4 Kg of nitrogen gas take up at 27°C and 3 atm?

23. The dirigible Hindenburg had 3.7E6 m³ of hydrogen in its gas bags at 1.1 atm and 7°C. What was the weight of the hydrogen in pounds?

Answer

16. 5.56 E5 L	17. 33.5 L
18. 35.4 Atm.	19. 532 ml	20. 2.12 Kg	21. 209 KL
22. 1.17 KL	23. 7.80 E5 L

Gas Law problems with solution Part - 3

11. What is the mass of 15 liters of chlorine gas at STP?


12. How many liters of ammonia at STP are produced when 10 g of hydrogen is combined with nitrogen?

13. How many milliliters of hydrogen at 0°C and 1400 mmHg are produced if 15g of magnesium reacts with sulfuric acid?

14. What is the mass of 25 liters of fluorine gas at 2.85 atm, 450°C?

15. A nine liter tank has 150 atmospheres of bromine in it at 27°C. What is the added mass of the tank due to the gas?

Answer

11. 47.5 g	12. 74.7 L	13. 7.51 L
14. 45.6 g	15. 8.76 Kg

Problems on Concentration and solution making - Part 2

11. How many moles of NaCl are in 68 mL of a 0.15 M NaCl solution?
(That is physiological saline when sterilized.)
 
12.How many grams of NaCl do you have to put into a 5 liter container to make a physiological saline solution?

13. What volume of physiological saline solution would give you a gram of salt when evaporated?

14. What is the concentration of KCl if ten grams are dissolved in enough water to make 12 liters?



15. Sodium hydroxide and hydrochloric acid combine to make table salt and water. 14 mL of 0.1 M sodium hydroxide is added to an excess of acid. How many moles of table salt are made? How many grams of salt is that?

16. 50 mL of 0.25 M copper II sulfate evaporates to leave CuSO4 · H2O. (That is the pentahydrate crystal of copper II sulfate.) What is the mass of this beautiful blue crystal from the solution?

17. Chlorine gas is bubbled into 100 mL of 0.25 M potassium bromide solution. This produces potassium chloride and bromine gas. The bromine (which dissolves in water) is taken from the solution and measured at 27°C and 825 mmHg. What is the volume of bromine?

18. 95 mL of 0.55 M sulfuric acid is put on an excess of zinc. This produces zinc sulfate and hydrogen. How many grams of zinc sulfate are made?

19. 27.6 mL of a 0.19 M solution of silver nitrate and 15.4 mL of an unknown (but excess) amount of sodium chloride combine to make a white precipitate silver chloride and some dissolved sodium nitrate. (a) How many moles of silver chloride are made? (b) How many grams of silver chloride is that? (c) How many moles of sodium nitrate are made? (d) What is the concentration of sodium nitrate in the final solution?

20. What mass (how many grams) of potassium permanganate, KMnO4, is needed to make 1.72 liters of 0.29 M solution?

21. By my calculations, a drop of ethyl alcohol, C2H5OH , in an olympic-sized swimming pool produces a 1.2 E-10 M solution of alcohol in water. A drop is a twentieth of a mL. How many molecules of ethyl alcohol are in a drop of the water in the pool?

22. 93 mL of 0.15 M magnesium hydroxide is added to 57 mL of 0.4 M nitric acid. (Magnesium nitrate and water are formed.) What is the concentration of the magnesium nitrate after the reaction?

23. Does concentration ruin your concentration?

Answer

11. 10.2 millimols
12. 43.9 g	13. 0.114 L	14. 0.0112 M
15a. 1.4 E-3 mols	15b. 0.0819 g	16. 3.12 g
17. 284 ml	18. 8.44 g	19a. 5.24 E-3 mols
19b. 0.752 g	19c. 5.24 E-3 mols	19d. 122 mmolar
20. 78.8 g	21. 3.61 E9 molecules	22. 0.152 M

Problems on Concentration and solution making - Part 1

1. Explain how to make up five liters of a 0.175 M NaCl solution.

2. What volume of 0.86 M table sugar (C12H23O12) has 50 grams of sugar in it?

3. How many grams of KMnO4 would you get if you evaporated the water from 85.75 mL of 1.27 M solution?

4. To what volume must you dilute 15 grams of silver nitrate to make it 0.05 M?

5. What is the concentration of KCl if five grams of it are in 25.3 L?

6. How many moles of chlorine gas are in 17 L of 1.02 M solution?

7. How many grams of sulfuric acid are in 5 mL of 3.2 M acid?

8. I make up 500 ml of 0.1 M sodium hydroxide solution. Explain how I did it.

9. To what volume must you take 27 g of table salt if you want a physiological saline solution? (Physiological saline is 0.15 M NaCl.)

10. What is the concentration of silver nitrate if 15 grams of it are dissolved into 14.28 liters?

Answer

1. (a) Weigh out 51.2 grams of NaCl. (b) Dissolve the solid in a small amount of water in a suitable volumetric device. (c) Bring the solution to volume by adding water (q.s.) and mix to completely disburse.
2. 0.162 L	3. 17.2 g	4. 1.77 L
5. 2.65 m mols	6. 17.34 mols	7. 1.57 g
8. (a) Weigh out 2.00 grams of NaOH. (b) Dissolve the solid in a small amount of water in a suitable volumetric device. (c) Bring the solution to volume by adding water (q.s.) and mix to completely disburse.
9. 3.08 L	10. 6.18 m molar

Chemistry problem and solution - Reaction rate

Problem
Given the following reaction: 3H2(g) + N2(g) ←→ 2NH3(g) + 22 kcal heat energy. What is the heat of reaction for the reverse reaction? What would you do to the temperature, pressure, and concentrations of the reactants and products to shift the equilibrium so that more ammonia is made?

 Solution:
The ΔH for the reverse reaction will have a positive sign because the reverse reaction is endothermic. The ΔH is equal to + 22 kcal. To shift the equilibrium to make more ammonia, start by adding more hydrogen
gas and nitrogen gas because having more reactants present will make more products. Because the heat energy is a product, you do not want to add heat. You would have to lower the temperature to remove the
heat so that the reaction will shift to the right in an effort to replace the heat. Because there is a total of four volumes of gas on the left and two volumes of gas on the right, an increase in pressure will favor the production of ammonia because it is the side with fewer volumes of gas.

Online problems and solutions in Chemistry

Calculate the number of grams of silver chromate formed from 25.0 mL of 0.125 M silver nitrate and 15.0 mL of 0.120 M potassium chromate.

Step 1_ Write and balance the reaction to see how many moles of silver nitrate could form from a mole of each reagent
2AgNO₃ + K₂CrO₄ → Ag₂CrO_{4 +} 2KNO₃
Each mole of K₂CrO₄ can react with 2 moles of AgNO₃ to produce 1 mole of Ag₂CrO₄.
Each mole of AgNO₃ can react with 0.5 moles of K₂CrO₄ to produce 0.5 mole of Ag₂CrO₄.
Step 2_ Calculate how many moles of each reactant you have.
(0.0250 L)(0.125 mol/L) = 0.003125 moles of AgNO₃
(0.0150 L)(0.120 mol/L) = 0.00180 moles of K₂CrO₄
Step 3_ Figure out how much product will form, and which reactant is the limiting reagent (or if they are present in equivalent amounts).
Since each mole of K₂CrO₄ can react with 2 moles of AgNO₃, 0.00180 moles of K₂CrO₄ could react with 0.00360 moles of AgNO₃. However you do not have that much AgNO₃. Silver nitrate is the limiting reagent, and K₂CrO₄ is in excess.
0.003125 moles of AgNO₃ will react with 0.00161 moles of K₂CrO₄ to produce 0.00161 moles of Ag₂CrO₄.
Step 4_ Find the molecular weight (or formula weight) of Ag₂CrO₄, and calculate the number of grams formed.
Your instructor probably expect you to find the fromula weight for Ag₂CrO₄ by adding atomic weights. I added up to 331.73. That would mean 1 mole has a mass of 331.73 g
(0.00161 moles)(331.73 g/mol) = 0.534 g Ag₂CrO4