Identify the composition of caffeine. C8H10N4O2 *

C=?, H=?, N=?, O=?

Why does a metal spoon left on a bowl of hot soup get warm?

Which one is a true statement about endothermic reactions? a: More heat is given off than is put into the reaction. b : The reactants have more heat energy than the products. c: The reaction container always feels hot.

Convert 23.92inHg to Torr.

It is found when an unknown solid solute is dissolved in water that the solubility of the solid increases if temperature is decreased.

Radioactive elements decay at a know rate known as half-life. Choose all of the correct statements concerning half-life. Carbon-14 has a half-life of 5,730 years. A 30 gram sample will be 10 grams after 5,730 years.

Which of the following is an example of a physical change? A) grinding coffee beans B) baking a cake C) converting water to hydrogen and oxygen D) digesting a cheeseburger E) burning coal

Which substance is a combination of different atoms? homogeneous mixture heterogeneous mixture element compound

What is the mass of 3.75 moles of NaCI? (Na = 22.99g/mol, CI = 35.45 g/mol)

Convert to grams 0.100 moles of Co2

In order to use the value 22.4 L for molar volume in a mass-volume or volume-mass stoichiometry problem, the gas must be assumed to be at STP. A. True B. False