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Describe the difference between the temperature vs time cooling curve of a pure substance and a solution.
Briefly, explain how to make an acetic acid/ acetate buffer? Give the chemical reaction between this buffer and a small addition of base (OH-), which explains why the pH of the solution remains abou
Which of the following reagents might serve as the basis for a simple chemical test that would distinguish between pure 1-hexane?
The molecule H2S2 has a linear arrangement of its atoms. Number all sulfur atoms along the chain from 1 to 4. Find the oxidation number of each sulphur in the molecule from the first to the fourth.
The vapor pressure of a water-insoluble organic substance is negligible at 100 degree C. Can this substance be purified by steam distillation? explain.
A 17.9 g sample of an alloy at 98.0°C is placed into 127.2 g of water at 22.0 °C in an insulated coffee cup with a heat capacity of 9.2 J/K. If the final temperature of the system is 35.0&de
A sample of N2(g) was collected over water at 25 degrees Celcius and 730 torr in a container with a volume of 340 mL. The vapor pressure of water at 25 degrees Celcius is 23.76 torr. What mass of N2
If the half-life of a radioactive element is 30.0 years, how long will it take for a sample to decay to the point where its activity is 70.0% of the original value?
Rhenium-186 is a ß-emitter with a half-life of 90.0 hours. How long would it take for the activity in a sample of this isotope to decay to exactly one-third of its original value?
The solubility product for cerium(III) fluoride is 8.0 x 10^-16 (A) what is the molar solubility of Cerium (III) Fluoride in water?
At 298 K a cell reaction has a standard emf of +0.17 V. The equilibrium constant for the cell reaction is 5.5 105. What is the value of n for the cell reaction?
A scanning electron microscope operating at an accelerating voltage of 10 kV accelerates electrons to 20% of the speed of light, calculate the wavelength of the electron.
Question: An unknown mass of each of the following substances, initially at 24.0 C, absorbs 1920 J of heat. The final temperature is recorded as indicated. Find the mass of each substance.
Calculate the volume (in mL) of a 1.22 M Na2S solution needed to react with 2.75 g of AlBr3 (molar mass = 266.7 g/mol) in the following reaction:
Would the calculated value of k, the true rate constant, be in error if the concentration of dye was actually doubled the value you were told? Explain your answer.
A cylinder containing 23.5 moles of nitrogen gas has a volume of 9.81L. What is the pressure of the gas at 23°C?
A chunk of gold with an unknown mass is heated to 163 degrees C and dropped into 38.0 grams of water at 25.0 degrees C. If the final temp of the water is 36.5 degrees C, what is the mass of the gold
An element crystallizes in a body-centered cubic lattice. The edge of the unit cell is 2.52 \AA, and the density of the crystal is 6.11 {\rm g/cm^3}
What mass in grams of hydrogen is produced by the reaction of 4.73 g of magnesium with 1.83 g of water?
The average distance between Mars and Earth is about 1.3 x 10^8 miles. How long would it take TV pictures transmitted fromt he Viking space vehicle on Mars' surface to reach Earth? ( 1 mile = 1.61 k
Carbon dioxide is dissolved in an aqueous solution at 303 K at a concentration of 0.90 x 10-4 kg/kg. Henry's Law constant at these conditions is 0.186 x 104 atm. What is the partial pressure of CO2 in
Which of the binary compounds formed by the following pairs of elements contain polar covalent bonds?
A gas filed ballon having a volume of 2.50L at 1.2 ATM and 20 degrees celcius is allowed to rise to the stratosphere where the temperature and pressure are -23 degrees celcius and 3.00 x 10^-3 atm r
A sample of nitrogen in a 4.5L container at a temperature of 27 degrees C exerts a pressure of 4.1 atm. Calculate the number of moles of gas in the sample.
Sodium bicarbonate is reacted with concentrated hydrochloric acid at 37.0°C and 1.00 atm. The reaction of 6.00 kg of bicarbonate with excess hydrochloric acid under these conditions will produce