Share
Explore BrainMass

Stoichiometry

Simplest Formula Analysis

50.0 g of an oxide of Chromium (Cr) was found to contain 13.28g of potassium (K), 17.68 g of Chromium (Cr) and 19.04 g of oxygen (O). Find the simplest formula...

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.

What is the oxidation reaction for Ag + NaCl?

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

Calculating ppm

The chloride in a saline solution was determined by the Volhard method. A 25 ml aliquot of the solution was acidified with 2 ml of dilute HNO3 and treated with 25 ml of .1749 M AgNO3 (fw 169.9), causing precipitation of AgCl. After addition of several ml of nitrobenzene, the solution required 26.40 ml of .1575 M KSCN to reach t

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.

Density

A cube of material with a length of 0.044 m and mass of 10.00 X 10 to the negative 1 power kg. What is the density (g/mL)?

Density

What is the density of a 100.000 grams cubic object that has a length of 0.025 meters?

Nuclear Reaction Question

In spontaneous nuclear reactions: a. the products weigh less than the reactants b. the products weigh more than the reactants c. the difference in mass between reactants and products is zero d. mass is converted to light e. the products move at the speed of light squared

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