Explore BrainMass

General Chemistry

Gas Constant

When do you use 0.08206 l atm versus 8.345 l atm? Can you tell me how you decipher when to use one or the other generally? Thank you.


How can i find the pressure of oxygen if it's in a mixture of .40 moles of oxygen and .20 moles of nitrogen at 1.2 atm pressure

Partial pressure

I cant remember how to find the partial pressure of o2 when the container has .76 mol of N2, .18 mol of O2, .031 MOl of He, and .026 mol of H2 at 744mmHg.

Combustion of c3h5n3o9

I cant remember how to find the volume of the gas produced when 1kg of nitroglycerine explodes at a temp of 1985*C at 1 atm.

Calculating volume of water evaporated

A 230mL sample of a 0.276 M CaCl2 solution was left on a hot plate overnight; the following morning, the solution is 1.10 M. What volume of water evaporated from the 0.276 M CaCl2 solution?

Solving a Wavefunction

Question: What is the complete wavefunction for n=2, L=0, and m(sub L)= 0? What radius of the orbital specified is required to contain 95% probability of finding an electron?

Measuring Water Hardness

In an experiment for measuring water hardness in a water sample, using Atomic Absorption Spectrophotometry, I obtained a value of 173.74 ppm hardness for my water sample. Using EDTA determination, I obtained a value of 440 ppm hardness for my sample. In both these methods, I was measuring the hardness in relation specifically to

Hazardous Dyes

Question: Many dyes used in food products are classified a hazardous chemicals in their pure form. Why then can they be safely used in those food products?

Kf & vapor pressure

A soluation of HO-CH2-CH2-OH is prepared by dissolving 651g of ethylene gylcol in 1.50kg of water. Determine the freezing point of the soluaiton and the vapor pressure of water above the solution 25.0 degrees C. The normal freezing point of water is water is 0.00 degrees C with a freezing oint depression constant of 1.86 degr

General Chemistry

5.17 A gas occupying a volume of 725 ML at a pressure of 0.970 atm is allowed to expand at constant temperature until its final volume?

General Chemistry

4.60 You have 505 ml of a 0.125M HCI solution , and you want to dilute it to exactly 0.100 M. How much water should you add?

General Chemistry

A quantity of 5.25 g of NaOH is dissolved in a sufficient amount of water to make up exactly 1L of solution. What is the molarity of the solution?

Jacobians and Polar Coordinates

Please view the attachment for proper formatting of the question. Question: The range of the polar coordinates are 0 <= r <= ~, 0 <= theta <= pi, and 0 <= phi <= 2pi and the range of the Cartesian coordinates are - ~ < x,y,z, < ~. In the integrals we must relate the two. This is done by the Jacobian, and the result is, d


Which, if any, of the following equations is or are correctly balanced? NH4NO3 N2 + O2 + H2O 3Cu + 8HNO3 3Cu(NO3)2 + 2NO + 4H2O 6CO2 + 6H2O C6H12O6 + 6O2 NaOH + Cl2 NaOCl + NaCl + H2O

Precipitate of AgCl

Will a precipitate of AgCl form whrn 0.050 mol NaCl(s) and 0.050 mol AgN0subnumber3(s) are dissolved in 500.0 milliliter of 3.0 mol/Litre NHsubnumber3 solution? (Kf for Ag(NH3)2^+ is 1.5x10^7) Ksp for AgCl = 1.6x10^-10

8 precipitate of magnesium flouride

Will a precipitate of magnesium flouride form when 200.0 milliliter of 1.9x10^-3mol/Litre MgClsubnumber2 solution is added to 300.0 milliliter of 1.4x10^-2mol/Litre NaFsolution? (ksubletterssp(MgFsubnumber2)=6.9x10^-9) Briefly explain by showing your numerical calculations show work. thanks

Significant Figures - Scientific Notation

Need to calculate the average of the following two figures, and be sure to keep significant figures. 19.5 + 20.40 = 39.9 39.9 /2 = 19.95 If the answer is 19.95, what is the answer using significant figures only? Can the answer containing significant figures be put into scientific notation?

Conversion factors

Convert the following to the required units: 550 uL (microliters) per hour to milliliters per day Please show steps

Word problem: Convert uL to mL

A nurse plans to five flu injections of 50 uL (microliters) each from a bottle containing 2.0 mL of vaccine. How many doses are in the bottle? Please show steps to get answer.


The following ions all have the same number of electrons: See attached file for full problem description. Order them according to their expected size, and explain answer.