What period of the mesozoic era did dinosaurs first appear

Which of the following is NOT a characteristic of most ionic compounds?

Ergosterol, a precursor of vitamin D, has δmax = 282 nm and molar absorptivity ε = 11,900 M-1cm-1. What is the concentration of ergosterol in a solution whose absorbance A = 0.43 with a sample pathlength l = 1.00 cm.?

To what Celsius temperature must 67.0 mL of krypton gas at 18.0°C be changed so the volume will triple? Assume the pressure and the amount of gas are held constant. Enter your answer to four significant figures.

True or false after a volcanic eruption it is nearly impossible for plant life to grow due to poor soil

What happens when the silvered coin is put on the flame

Raising the temperature of a reacting system increases the rate of the reaction, but does NOT increase the a) activation energy b) number of collisions c) fraction of the reacting particles which possess energies greater than the activation energy

If you have 60 grams of MgCl2 in 5 liters of solution, what is the molarity of this solution?

Is evaporation/condensation a physical or chemical change? Explain

Would the two as yet undiscovered elements A+1 and D+2 react?

Ammonium perchlorate is a powerful solid rocket fuel, used in the Space Shuttle boosters. It decomposes into nitrogen gas, chlorine gas, oxygen gas and water vapor, releasing a great deal of energy.