Which of the following describes an endothermic reaction?

Thermal energy is released by the system.

Thermal energy is absorbed by the surroundings.

Thermal energy is absorbed by the system.

Thermal energy is not transferred.

A clear liquid in an open container is allowed to evaporate. after three days a solid residue is left. was the original liquid an element, compound, or mixture? how do you know?

At equilibrium the concentration of lack is about ten times higher than the concentration of l2

A sample of nitrogen gas has a volume of 578 mL and a pressure of 124.1 kPa. What volume would the gas occupy at 80.2 kPa if the temperature remains constant?

In a chemical reaction, if a color change is detected, if an odor change is detected, or if a precipitate is formed, then: a chemical reaction has definitely occurred only physical reactions have occurred a chemical reaction may have occurred both

How do you calculate wavelength?

What is the density of an object having a mass of 8.0g and a volume of 25cm3

What is a Cilla? (In drawing)

Which term names the group of organisms able to interbreed and produce fertile offspring?

A sample of a compound contains 32.0 g C and 8.0 g H. Its molar mass is 30.0 g/mol. What is the compound's molecular formula

What is the molecular formula of the compound CH2 with molar mass = 42.0 g/mol? C4H8 C3H6 C2H4 C2H18