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.
There are actually five. 1.Colour Change (permanent) 2.Property Change 3.Gas Production 4. Precipitate 5. Heat,energy,light and electricity produced
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.
synthesis, decomposition, single replacement, and double replacement
Things can blow up, or even cause a radiation reaction
Examples:
- a change of color
- a change of temperature
- a change of composition
- a change of viscosity
A chemical reaction can change a substance into a solid, liquid, or gas. It may cause a substance to explode or could cause no change at all.
- the volume increase- the density decrease- a chemical reaction may occur- a change of phase is possible
Chemical, (biological, bio-organically), definitely NOT physical.
change in clour state and if bubbles form.
Ammong other things, you get poisonous gasses.
a substance that results from a chemical change
A chemical reaction can change a substance into a solid, liquid, or gas. It may cause a substance to explode or could cause no change at all.
Things can not be a chemical change. This question needs rephrasing. "What things undergo chemical change" maybe a better question but even then the question would be too broad.
Burnig things is always a chemical change.
change in properties and changes in energy
- the volume increase- the density decrease- a chemical reaction may occur- a change of phase is possible
color change, formation of a gas, formation of a precipitate, change in temperature, a solid disappears, a new odor is produced
Chemical, (biological, bio-organically), definitely NOT physical.
No, the formation of soap scum is not a chemical change. Soap scum appears as the result of a physical change. Some of the soap and whatever has become incorporated into the soap and water dry. After the water is gone, the things left are from the soap and whatever mixed with the soap when it was "working" at cleaning.
You can add a catalyst, or raise the temperature, or change the pressure, these are some of the things done to speed up a chemical reaction.
Lightning is a physical change not a chemical change. Other things that are physical changes are breaking a bottle and melting ice.
If an object has changed its chemical composition it has been through a chemical change. If you can't reverse what has been done in any way (things like burning, mixing, rusting) it's a chemical change