What are the signs you can see that would show you a chemical reaction has occurred?

Ethyl chloride (c2h5cl) boils at 12∘c. when liquid c2h5cl under pressure is sprayed on a room-temperature (25∘c) surface in air, the surface is cooled considerably.

Unknown element x has four energy levels, five valence electrons, and is a metalloid. what is elements x? a-Si b-Se c-Ge d-As

A confused student was doing an isomer problem and listed the following six names as different structural isomers of C7H16. a. 1-sec-butylpropane b. 4-methylhexane c. 2-ethylpentane d. 1-ethyl-1-methylbutane e. 3-methylhexane f.

When heat energy is removed, two changes are observed: Change A: Gas changes phases to a liquid. Change B: Liquid changes phases to a solid. What are the names for phase changes A and B? A is condensation and B is freezing.

The best way to reduce the symptoms of hyponatremia would be to a) drink water b) eat chocolate c) eat salty foods d) drink cranberry juice

Why did most scientists reject Wegner's theory for nearly a half century?

Define prediction and explain how it is used to formulate a hypothesis.

A group of organisms that breed and produce offspring that can breed. A. Species B. ecosystem C. Biodiversity

What is the molality of a solution containing 100 grams of glucose (C6H12O6, molar mass = 180 g/mol) dissolved in 2.5 kg of water? 0.22 m 72 m 7200 m 40 m

A battery is constructed based on the oxidation of magnesium and the reduction of cu2+. the initial concentrations of mg2 + and cu2 + are 1.2*10-4 m and 1.44 m, respectively, in 1.0-liter half-cells. how long can the battery deliver 5.