Upon heating, potassium chlorate decomposes to potassium chloride and oxygen gas. The oxygen gas is collected over water at 14.0 °C in a 500.-mL container. If the total pressure is 766 torr,

How many mol of oxygen gas is in the container?
What is the mole fraction of oxygen gas in the container?.
(Mole fraction = mole of substance of interest / mole of the system)

How many grams of potassium chlorate is decomposed?

A 12.0 % NaCl_(aq) has a density of 1.05 g/mL. What is the molality of the solution?

A 2.55 L sample of gas at STP contains hydrogen and oxygen gases. The mole fraction of hydrogen is 0.60. When the sample is combusted to form water, calculate the mass of water formed, assuming complete reaction.

A heater burns normal octane (n-C₈H₁₈) using 20.0 percent excess air. Combustion is complete. The flue gas leaves the stack at a pressure of 100 kPa and a temperature of 160⁰C.

a) Calculate the complete flue gas analysis.

b) What is the volume of the flue gas in cubic meter per kg mol of n-octane?

20#15

Given the following half-reactions and associated standard reduction potentials:
AuBr−4(aq)+3e−→Au(s)+4Br−(aq)
E∘red=−0.858V
Eu3+(aq)+e−→Eu2+(aq)
E∘red=−0.43V
IO−(aq)+H2O(l)+2e−→I−(aq)+2OH−(aq)
E∘red=+0.49V
Sn2+(aq)+2e−→Sn(s)
E∘red=−0.14V

a) Write the cell reaction for the combination of these half-cell reactions that leads to the largest positive cell emf.

b) Calculate the value of this emf.

E∘max = _____ V

c) Write the cell reaction for the combination of half-cell reactions that leads to the smallest positive cell emf.

d) Calculate the value of this emf.

E∘min = _____ V

What is the pH at the equivalence point 10.0 mL of 1.00 M NH₃ (K_b = 1.8 x 10^-5) is titrated against 2.00 M HCl?

At 1 atm, how much energy is required to heat 73.0 g of H2O(s) at –22.0 °C to H2O(g) at 121.0 °C?

1. What is the principal use of calcium proprionate (the calcium salt of propionic acid) based from The Merck Index?

2. What is the result of treating calcium chloride with oxalic acid?

3. Explain why oxalic acid can be a deadly poison?

How many unique 1 H NMR signals exist in the spectrum of the following compound: 1,3-dibromobenzene?

Cyanide recovered from the refining of gold ore
can be determined indirectly by EDTA titration. A known
excess of Ni2 is added to the cyanide to form tetracyanonickelate(
II):
4CN + Ni ---> Ni(CN)4
When the excess Ni2 is titrated with standard EDTA,
Ni(CN)4 does not react. In a cyanide analysis, 12.7 mL of
cyanide solution were treated with 25.0 mL of standard solution
containing excess Ni to form tetracyanonickelate. The excess
Ni required 10.1 mL of 0.013 0 M EDTA for complete
reaction. In a separate experiment, 39.3 mL of 0.013 0 M EDTA
were required to react with 30.0 mL of the standard Ni
solution. Calculate the molarity of CN in the 12.7-mL sample
of unknown.

1. Listed below are the atomic weight, density, and atomic radius for three hypothetical alloys. For each determine its crystal structure and then justify your determination.

Alloy // Atomic weight (g/mol) // Density (g/ cm^3) // Atomic Radius (nm)

A // 43.1 // 6.4 // 0.122

B   // 184.4 // 12.3 // 0.146

C // 91.6 // 9.6 // 0.137

What is the molar solubility of CaF₂ in 0.10 M NaF solution 25 degrees C?

The K_sp for CaF₂ is 3.4x10^-11.

The answer is 3.4x10^-9 M. Please explain how to get to that answer. Thank you!

Calculate the following quantities for the reaction in which ammonia is formed from its atomic components:

a) The stoichiometric coefficients of the reactants and products.

b)The stoichiometric ratio of N₂ to H₂.

c)(moles NH₃ produced)/(mole N₂ reacted)

d)(lb_m H₂ reacted)/(lbmole NH₃ produced)

e)The Kmole of N₂ and H₂ that must react to form 150 Kmoles of NH₃.

f)The lb_m of NH₃ produced and lb_m of H₂ reacted if 20 lb_m of N₂ react completely.

Saturdated water vapor (steam) is commonly used as a heat source in heat exchanger applications. Why saturated vapor? Why saturated water vapor? In a plant of any reasonable size, several varieties of saturated steam are commonly available; for example, saturated steam at 4.5,9,17, and 33 bar. But the higher the pressure the lower the useful energy content (why?), and the greater the unit cost. Why then is higher-pressure steam used?

calculate the ph of a solution made by mixing 20.0 ml of 0.200 m h2so3, 10.0 ml of 0.120m naoh, 10.0ml of 0.150 m hcl, and 10.0ml of 0.200 m na2so3. (pka1: 1.857, pka2: 7.172 for h2so3)