What four things can happen as a result of a chemical change?

Answer 1

ako si Juan Pogi

1.A color change. A new color appears, which indicates that a new substance is present.

This substance was not present before the reaction, because its color was not observed.

An example would be an apple which turns brown when the fleshy part is exposed to the

air.

2. The formation of a gas. Sometimes, in the lab, you will see a gas rise from a solution.

For example, when magnesium metal is dropped into hydrochloric acid you will see

hydrogen gas bubbles rise to the top of the acid solution. Another example is the gas

which comes out of the exhaust of a car.

3. The formation of a precipitate. A precipitate is an insoluble product which forms as a

result of chemical change. Usually, you will see a precipitate when two solutions are

mixed. You will see a solid form which will fall (precipitate) to the bottom of the test

tube. Usually, a color change will accompany the formation of a precipitate.

4. Energy change. In an energy change, heat will be given off or absorbed. In an

exothermic reaction, energy is given off. You will note an increase in the temperature

and/or light - the solution will get hot. In an endothermic reaction, heat will be

absorbed, in which case the temperature will decrease - the solution will feel cold.

Burning gasoline in a car engine is exothermic; an instant ice-pack is an example of an

endothermic reaction.

Answer 2

There are actually five. 1.Colour Change (permanent) 2.Property Change 3.Gas Production 4. Precipitate 5. Heat,energy,light and electricity produced

Answer 3

1. no reaction
2. decompostion
3. reduction-oxidation
4. ion trade with possible insoluable deposition
5. concatination
6. dehydration
7. saturation

Answer 4

The evolution of gas could happen in a chemical reaction. The change in temperature is when heat is produced. The formation of precipitate is when a new solid substance that forms.

Answer 5

synthesis, decomposition, single replacement, and double replacement

Answer 6

Things can blow up, or even cause a radiation reaction

Answer 7

Examples:

- a change of color

- a change of temperature

- a change of composition

- a change of viscosity