[CHEM 1000] - Final Exam Guide - Ultimate 164 pages long Study Guide!

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29 Nov 2016

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Not readily observable: mass of molecules, molecular speed, energy, collison frequency. To hold gas, you must have a gas capable of exerting a force on it (e. g. walls of balloon) Gas is exerting a balancing force on the container. To measure gas, have it balance a liquid. Consider cylinder of liquid q/ area(a) & height (h) Force exerting at bottom of cylinder is weight f=m(g) Density of liquid is d=m/v so m=v(d) v=a(h) Right tube is closed & liquid column is supported by atmospheric pressure. Fo(cid:396) (cid:271)a(cid:396)o(cid:373)ete(cid:396) p=g(cid:894)h(cid:895)(cid:894)d(cid:895), (cid:449)e ha(cid:448)e (cid:272)o(cid:374)sta(cid:374)t (cid:862)g(cid:863) & (cid:862)d(cid:863). Liquid (mercury) responds to the difference in gas pressures. Average pressure at sea level will support a column of 760mm of mercury. Definition of pressure unit of atmospheres : 1 atm= 760mm hg. Unit mm hg is known as torr. 1 atm= 760 mm hg= 760 torr. Like barometer but measures pressure differences using liquid.

Related Questions

1- (A) A 41 L cylinder containing helium gas at a pressure of 46.7 atm is used to fill a weather balloon in order to lift equipment into the stratosphere. To what maximum pressure (in atm) could a 286 L balloon be filled.

(B) A 38.0 L cylinder containing helium gas at a pressure of 20.9 atm is used to fill a weather balloon in order to lift equipment into the stratosphere. What is the final pressure (in atm) in the cylinder after a 169 L balloon is filled to a pressure of 1.15 atm.

(C)The following procedure provides a crude method of determining the molar mass of a volatile liquid. A liquid of mass 0.0181 g is introduced into a syringe and the end is capped (sealed). The syringe is transferred to a temperature bath maintained at 59.4 ^oC, and the liquid vaporizes. As the liquid vaporizes the plunger is pushed out. At equilibrium, the plunger reads 6.61 mL of gas. Atmospheric pressure is 740. mmHg. What is the approximate molar mass of the compound (in g/mol)?

(D)The reaction of magnesium metal with HCl yields hydrogen gas and magnesium chloride. What is the volume, in liters, of the gas formed at 757 torr and 34 ^oC from 4.59 g of Mg in excess Hal?

(E)What mass of water (in grams) forms from the reaction of 2.60 L of hydrogen gas and 1.97 L of oxygen gas? Both gases are at 698 torr and 12.9 ^oC.

(F)What is the partial pressure of argon, in torr, in a container that also contains neon at 220 torr and is at a total pressure of 439 torr?

(G)What is the total pressure if a container contains 10 torr of He gas, 207 torr of N₂ gas, and 72 torr of Ar gas?

(H)Oxygen gas is collected over water. The total pressure (the O₂ pressure + the water vapor pressure) is 760 torr. The temperature of the water is such that the water vapor pressure is 49 torr. What is the partial pressure of the oxygen gas in torr?

(I)A 5.10 L sample of neon at 10.11 atm is added to a 13.0 L cylinder that contains argon. If the pressure in the cylinder is 7.92 atm after the neon is added, what was the original pressure (in atm) of argon in the cylinder?

(J)Calculate the total pressure, in atm, in a 5 L flask that contains 6.42 g of Ne and 1.55 g of Ar. The temperature of the gases is 32 ^oC.

(K)Calculate v_rms, the root mean square velocity, in m/s of SO₂ molecules at 274 ^oC.

(L)An effusion container is filled with 7 L of an unknown gas. It takes 132 s for the gas to effuse into a vacuum. From the same container under the same conditions--same temperature and initial pressure, it takes 335 s for 7.00 L of O₂ gas to effuse. Calculate the molar mass (in grams/mol) of the unknown gas.

(M)Three bulbs are connected by tubing, and the tubing is evacuated. The volume of the tubing is 28.0 mL. The first bulb has a volume of 83.0 mL and contains 5.10 atm of argon, the second bulb has a volume of 250 mL and contains 1.09 atm of neon, and the third bulb has a volume of 33.0 mL and contains 4.04 atm of hydrogen. If the stopcocks (valves) that isolate all three bulbs are opened, what is the final pressure of the whole system in atm?

(N)Use the van der Waals equation to calculate the pressure, in atm, of 45.61 mol of hydrogen at 443 ^oC in a 2.45 L container.

WORD BANK:

Atomic solids

Body-centered cubic

Boiling point

Condensation

Covalent atomic solids

Crystal lattice

Crystalline solids

Distillate

Distillation

Dynamic equilibrium

Evaporation

Face-centered cubic

Freezing

Freezing point

Ionic solids

Intramolecular

Interionic forces

Intermolecular forces

Liquid State

Macromolecule

Melting

Melting point

Metallic atomic solids

Molar heat of fusion

Molar heat of vaporization

Molecular solids

Non-bonding atomic solids

Non-crystalline (amorphous) solids

Properties of Liquids

Properties of Solids

Simple cubic

Solid State

Sublimation

Surface tension

Surfactants

Vapor pressure

Vaporization

Viscosity

Wetting action

Use the Vocabulary words above to complete the following sentences words can be used more than once, some words are not be used.

d. The molecules of a ________ are in constant motion. e. The __________ of a liquid is related to the shape of the molecules that make up the liquid. f. The force of attraction that causes the surface of a liquid to contract and form a âbeadâ or spherical drop is called? _________ _______ g. Chemical that reduce surface tension are called? __________ h. A liquids ability to spread out evenly over a surface as a thin film is called itâs? _________ _______ i. ____________ is the process by which molecules of a liquid break away and go into the gas phase. j. When the molecules of a volatile liquid jump to gas phase it is called _________. k. The reverse of evaporation (the conversion of a vapor to a liquid) is called? _________ l. When the rate at which the water is evaporating is equal to the rate at which the water vapor is condensing, you have established a __________ _________. m. ________ _______ is the partial pressure of a gas in dynamic equilibrium with its liquid. n. ________ _______ is when the vapor pressure equals the atmospheric pressure. o. Boiling point can be used to purify a solution of two or more substances by ________. p. The condensed vapor sample is called the? ________ q. The exact quantity of heat required to vaporize 1 mole of a liquid at constant pressure and temperature is called the ________ ________ ___ __________. r. In ________________ __________ the particles do not have a definite or regular order (there is no repeating pattern throughout the solid). s. In ____________ __________, the particles are arranged in regular, systematic patterns called a ________ _________. t. The three different types of crystal lattices based on the cube are? ________ ______, _____________ ______, and ___________, ________. u. The three types of atomic solids include _________ _____, ___________ ______, and __________ ________.

I need help writing a decent conclusion. Every time I submit a lab report the professor slams my conclusion saying it needs work. She wants us to state what the results mean and if they are as expected and explain the possible reasons for variation in your results. The lab is below with data/results. Please, please help.

The Ideal Gas Equation: The Determination of Gas Constant, R

Introduction:

The purpose of this experiment is to determine the gas constant R and the percentage of KClO₃ in the KClO₃ â KCl â MnO₂ mixture using the moles of O₂, the original weight of the mixture, and the stoichiometry of the reaction. Consider a plot PV vs. nT for a gas sample where P is the pressure of the gas, V is the volume occupied by the gas, n is the number of moles of gas, and T is the temperature of the gas in Kelvin. If the temperatures and pressures fall in normal ranges, the plot will yield a straight line. Thus, PV = nRT where R is the constant of proportionality between the PV product and the nT product. The object of this experiment is to determine P, V, n, and T for a gas sample and determine the gas constant R, using the equation PV = nRT. The gas sample used will be a sample of oxygen gas generated by the MnO₂ catalyzed decomposition of KClO₃. Following is the equation of the reaction:

For decomposition of the KClO₃ in a KClO₃ â KCl â MnO₂ mixture, the mass of O₂can be determined by taking the difference between the mass of the original mixture and the mass of the residue after the decomposition. This mass is then converted to moles of O₂ using the molecular weight of oxygen. The volume of the sample will be determined by water displacement in such a way that the pressure of the sample can be determined from the barometric pressure and the vapor pressure of water. The temperature of the sample will be directly measured.

Procedure:

Assemble the equipment for the apparatus shown in figure 1. With the Florence flask filled to the neck with water, the beaker one-third filled with water, and the pinch clamp open, blow into the tube which connects to the test to create a siphon between the flask and the beaker. Reverse the siphon a few times by raising and lowering the beaker. This will fill the tube connecting the flask and the beaker with water and will also remove air bubbles from the system. Adjust the siphon such that the flask is filled to the neck with water, and close the pinch clamp.

Weigh the eight inch test tube. Add approx. 1.5 grams of the KClO₃ â KCl â MnO₂mixture to the test tube and weigh the test tube containing the mixture. Record each weight to three decimal places. (Also, be sure and record the sample number for the KClO₃ â KCl â MnO₂.)

Clamp the test tube to the ring stand, and insert the stopper as shown in figure 1. With the pinch clamp open, raise the level of the beaker such that the water level in the beaker is several inches above the water level in the flask. If a significant amount of water runs into the flask, there is an air leak in the system. If you have an air leak, it must be closed before proceeding. Equalize the pressure in the flask with atmospheric pressure by bringing the water level in the beaker to the same height as the water level in the flask. After closing the pinch clamp, empty and dry the beaker. Open the pinch clamp. A small amount of water will run into the beaker: this will not affect your results since later in this experiment, you will again equalize the pressure in the flask with atmospheric pressure. Ask your instructor to check your apparatus before proceeding.

Heat the mixture with a blue flame until the mixture first begins to melt and then solidifies again; and then heat for an additional 2 mins. (Donât heat more than 7 mins.) Allow the system to cool for 15 mins. Equalize the pressure with atmospheric pressure, as before; then close the pinch clamp and open the system. Quickly measure the temperature of the gas in the flask; also measure the volume of water in the beaker. Record the barometric pressure reading from professor. Weigh the test tube with the residue and record the mass to three decimal places.

Data/Results:

	Trial 1
Weight of test tube	41.912 g
Weight of test tube + mixture	43.343 g
Weight of mixture	1.431 g
Weight of test tube + residue	43.211 g
Weight of oxygen	0.132 g
Moles of oxygen	0.00413 mol
Temperature of water (under oxygen)	21.0 ⁰C
Temperature of oxygen	20.5 ⁰C
Barometric pressure	761.5 torr
Vapor pressure of water	18.7 torr
Pressure of oxygen	742.8 torr
Volume of water displaced	0.101 L
Gas constant, R	61.9
Mass of KClO₃ in mixture (use balanced equation)	0.338 g
% of KCLO₃ in mixture	23.6 %

[CHEM 1000] - Final Exam Guide - Ultimate 164 pages long Study Guide!

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