Share
Explore BrainMass

Stoichiometry

Determine concentrations in mixture using determinants

Please see attachment. A solvent called "mixed xylenes" contains the o-xylene, m-xylene, p-xylene and ethyl benzene. In the table below, the absorbances of each of the pure components and the absorbance of a sample of "mixed xylenes" were measured at four different wavelengths. All measurements used the same cell and, theref

Physics

Imagine that we give N2(+), O2(+) and (NO)+ ions the same velocity of 30.0 km/s and then send them into a mass spectrometer where the magnetic field strength is B=8.5MN/C. How far would the spot on the photographic plate be from the entry point for each ion, assuming that each ion completes one-half of an orbit. The atomic mas

Determine Concentration of Potassium Chromate to Use (Mohr Titration)

A titration of 0.100 M Cl^- with 0.100 M Ag^+ used an end point where silver chromate gives an orange precipitate. Select the concentration of potassium chromate that must be present so the orange-colored silver chromate precipitate will appear just when 99.5% of the chloride has been precipitated. Given: Ksp of AgCl = 1.0 x 10

Oxygen reactions

Oxygen can be preparead in a lab by the reaction: 2KCLO3 = 2H2(g) + O2(g) Question: How many grams of KCLO3 must be reacted to produce 100 g of O2?

Daltons Law of Partial Pressures

Dry air near sea level has the following composition by volume: N_2, 78.08%; O_2 20.94%; Ar, 0.93%; CO_2 0.05%. the atmospheric pressure is 1.00 atm. calculate the partial pressure of each gas in atm and the concentration of each gas in moles per liter at 0 degrees C.

Gas stoichiometry

C2H5OH burns in air: C_2H_5OH(l)+O_2 --->CO_2(g)+H_2O(l) balance the equation and determine the volume of air in liters at 35.0 C and 790 mmHg required to burn 227 g of ethanol. assume that air is 21.0 percent O_2 by volume.

the percent silver of the dime in the oxidation reaction

For my AP chemistry lab, I was supposed to find the percent of silver in a dime. I started out with the formula: Ag + NaCl → AgCl +Na. The dime was put in a covered beaker with NaCl. However, during the experiment oxygen was added as one of the reactants, accidentally. The precipitated silver chloride was obviously con

Mass percentage of sodium chloride in a mixture

A sample of a mixture containing only sodium chloride and potassium chloride has a mass of 3.5650g. When this sample is dissolved in water and excess silver nitrate is added, a white precipitate (silver chloride) forms. After filtration and drying, this precipitate has the mass 7.9143g. What is the mass percentage of sodium ch

Find the mass percent of Tl2SO4.

The thallium (present as Tl2SO4) in a 7.80-g pesticide sample was precipitated as thallium(I)iodide. Calculate the mass percent of Tl2SO4 in the sample if 0.890g of TlI was recovered.

Atomic masses: relative abundance

The element Europium exists in nature as two isotopes: 151Eu has a mass of 150.9196 amu, and 153Eu has a mass of 152.9209 amu. The average atomic mass of europium is 151.96 amu. Calculate the relative abundance of the two europium isotopes.

Empirical formulae - the uses

A 1.000g sample of an unknown hydrocarbon containing only carbon and hydrogen is burned in excess oxygen to yield carbon dioxide and water. The masses of CO2 and H2O are 2.994g and 1.635g, respectively. What is the empirical(simplest) formula for this compound?

Finding molarity and the reactions and productions of a balanced equation

1.) What is the molarity of a solution made by dissolving 25.6 g of KOH (5601 g/mol) in enough water to make 3.00 L of solution? 2.) 2 Fe + 3 Cl2 ------> 2FeCl3 How many moles of Fe are needed to produce 76.4 g of FeCl3 (162.3 g/mol)? How many grams of Fe (55.8 g/mol) are needed to react with 123 g or cl2 (71.0 g/mo

Multiple choice question about the relationship between Q and Kp.

If the value of Q is greater than Kp, then a. the system is in equilibrium b. the reaction will proceed to the right until equilibrium is established c. a catalyst is necessary to achieve equilibrium d. the reaction will go left or right depending on the reaction stoichiometry e. the reaction will proceed to

Chemistry multiple choice questions (chem-2)

1. A collection of atoms, molecules, or ions that contains Avogadro's number of these items is called what? 2. The initial substances that undergo change in chemical reaction are called what? 3. The law that states that atoms are neither created nor destroyed in a chemical reaction, but may be rearranged, is called what? 4. T

Average Molar Atomic Weight of Chlorine

What is the average molar atomic weight of chlorine, if the natural abundance of Cl-35 and Cl-37 isotopes are 75.4 molar % and 24.6 molar %, respectively? M(Cl-35) = 34.969 g/mole M(Cl-37) = 36.966 g/mole.

Determining the formula of a hydrate.

When all of the water of hydration was driven off of 4.32g of a hydrate of compound Z, the residue, the anhydrous form of Z, had a mass of 3.09g. What is the formula of the hydrate (using the symbol Z as part of it)? The formula mass of Z is 90.0

Mixture- identity of metals

When 8.900 g of a mixture of an alkali metal chloride (XCl) and an alkaline earth chloride (YCl2) was dissolved in 150.0g of water, the freezing point of the resultant solution was -4.42C. Addition of an excess of aqueous AGNO3 to the solution yielded a white precipitate with a mass of 27.575 g (This white precipitate would be

Products of Radioactive Decays

What are the products of the following radioactive decays? A. Alpha emission by: 162 Re 75 B. Beta emission by: 188 W 74 C. Positron emission by: 165 Ta 73

Uses of mercury

1. Find out 2 or 3 uses for mercury. 2. For each use find out why mercury was chosen for the job 3. What are the dangers from using mercury.

Converting grams to kilojoules.

Burning 2.00g of propane, C3H8, produces 99.78 kJ of energy. How much energy is produced when one mole of the propane burns?