• Indonesian and Malay term for theater
• When the term is used to refer to kinds of puppet theater, sometimes the puppet itself is referred to as wayang

Labels: Music, Music of Indonesia

• Musical ensemble of Indonesia
• Features a variety of instruments such as metallophones, xylophones, drums, and gongs; bamboo flutes, bowed and plucked strings, and vocalists may also be included

• It typically consists of seven bronze bars placed on top of a resonating frame
• It is usually about 20 cm (8 in) high, and is played on the floor by a seated performer

• Largest member of saron group
• It has the largest metal bars and produces the lowest sound

• Mid-sized member of saron group
• It’s pitch is octave higher than the Saron Demung

• The smallest of the Saron family
• It is approximately two feet long

• Typically consists of 10 bronze keys suspended over tube resonators

• The middle-sized member of the gender family.
• It is approximately 42 in. long

• It is low in pitch, and its sound sustains for a relatively long period of time because of the tubular resonators below each bar.

• It is a collection of small gongs (sometimes called "kettles" or "pots") placed horizontally onto strings in a wooden frame either one or two rows wide
• Bonang Panerus is the highest of them, and uses the smallest kettles
• Bonang Barung is pitched one octave below the Bonang Panerus, and also generally covers two octaves
• Bonang Panembung is pitched the lowest

Labels: Gamelan, Music, Music of Indonesia

Sample Problems:

1. A mixture of 0.500 mol H₂ and 0.500 mol I₂ was placed in a 1.00-L stainless-steel flask at 430 ^oC. The equilibrium constant K_c for the reaction

H_{2 (g)} + I_{2 (g)} ←→2 HI _(g)

is 54.3 at this temperature. Calculate the concentrations of H₂,I₂ and HI

at equilibrium.

2. For the reaction H_{2 (g)} + I_{2 (g)} ←→2 HI _(g) at 430 ^oC, suppose that the

Initial concentrations of H₂,I₂ and HI are 0.00623 M, 0.00414 M and 0.0224 M, respectively. Calculate the concentrations of these species at equilibrium.

3. Consider the reaction H_{2 (g)} + I_{2 (g)} ←→ 2HI _(g) . Starting with the reaction of 0.040 M for HI, calculate the concentrations of H₂,I₂ and HI.

4. At 1280 ^oC the equilibrium constant (Kc) for the reaction Br_{2 (g)} ←→2 Br _(g)

is 1.1 x 10 ^-3. If the initial concentrations are [Br₂] = 6.3 x 10 ^-2 M and [Br] = 1.2 x 10 ^-2 M. Calculate the concentrations of these species at equilibrium.

5. In the reation: cis-stilbene←→trans-stilbene. The equilibrium constant for this system is 24 at 200 ^oC. Suppose that initially only cis-stilbene is present at a concentration of 0.850 mol/L. Calculate the concentrations of these species at equilibrium.

Labels: Chemistry Lecture, Sample Problems

• The ratio of initial concentrations of products to reactants is too small.
• To reach equilibrium, reactants must be converted to products.
• The system proceeds from left to right (consuming reactants, forming products) to reach equilibrium.

• The ratio of initial concentrations of products to reactants is too large.
• To reach equilibrium, products must be converted to reactants.
• The system proceeds from right to left (consuming products, forming reactants) to reach equilibrium.

Labels: Chemistry Lecture

Sample Problems:

1. At the start of a reaction, there are 0.249 mol N₂, 3.21 X 10 ^-2 mol H₂, and 6.42 X 10 ^{- 4} mol NH3 in a 3.50 L reaction vessel at 375 ^oC. If the equilibrium constant (Kc) for the reaction

N₂ (g) + 3 H₂ (g) ←→2 NH₃ (g)

is 1.2 at this temperature, decide whether the system is at equilibrium. If it is not, predict which way the net reaction will proceed.

2. The equilibrium constant Kc for the reaction:

H_{2 (g)} + I_{2 (g)} ←→ 2 HI _(g)

is 54.3 at 430 ^oC. Suppose that in a certain experiment we place 0.243 mole of H₂, 0.146 mole I₂ and 1.98 moles of HI all in a 1.00 L container at 430 ^oC. Will there be a net reaction to form more H₂ and I₂ or more HI?

3. The equilibrium constant (Kc) for the formation of nitrosyl chloride, an orange-yellow compound, from the nitric oxide and molecular chlorine

2 NO _(g) + Cl_{2 (g)} ←→2 NOCl _(g)

is 6.5 x 10 ⁴ at 35 ^oC. In a certain experiment, 2.0 X 10 ^-2 mole of 8.3 x 10 ^-3 mole of Cl ₂ and 6.8 moles of NOCl are mixed in a 2.0- L flask. In which direction will the system proceed to reach equilibrium?

Labels: Chemistry Lecture, Sample Problems

• concentrations of pure solids
• concentrations of pure liquids (in heterogeneous equilibria),
• solvents (in homogeneous equilibria

Sample Problems:

1. Consider the following heterogeneous equilibrium:

CaCO_{3 (s)} ←→CaO _(s) + CO_{2 (g)}

At 800 ^oC, the pressure of CO₂ is 0.236 atm. Calculate (a) K_c and (b) K_p for the reaction at this temperature.

2. Consider the following equilibrium at 395 K:

NH₄HS _(s) ←→NH_{3 (g)} + H₂S_(g)

The partial pressure of each gas is 0.265 atm. Calculate (a) K_c and (b) K_p for the reaction

3. The equilibrium constant Kp for the reaction

PCl5 _(g) ←→PCl_{3 (g)} + Cl_2(g)

is found to be 1.05 at 250 ^oC. If the equilibrium partial pressures of PCl₅ and PCl₃ are 0.875 atm and 0.463 atm, respectively, what is the equilibrium partial pressure of Cl₂ at this temperature?

4. The equilibrium constant Kp for the reaction

2 NO_{2 (g)} ←→2 NO _(g) + O_2(g)

is 158 at 1000 K. Calculate P_O2 if P_NO2 = 0.400 atm and P_NO = 0.270 atm.

Labels: Chemical Equilibrium, Chemistry Lecture, Sample Problems

Equilibrium constant (K)

A number equal to the ratio of the equilibrium conc. Of the products to the equilibrium concentrations of reactants, each raised to the power of its stoichiometric coefficient.

Law of mass action

For a reversible reaction at equilibrium and a constant temperature, a certain ratio of reactant and product concentrations has a constant value, K (equilibrium constant)

Acid Ionization Constant (K_a)

equilibrium constant for the acid ionization.

Base Ionization Constant (K_b)

Equilibrium constant for the base ionization

Ion-product Constant (K_w)

Labels: Chemical Equilibrium, Chemistry Lecture