To be certain that a chemical change has taken place you check the composition of the sample before and after the change. The following is a chemical property of water at 4 C is its ability to decompose into hydrogen and oxygen.
A physical change means that only the appearance of the substance has changed. So if your tear up a piece of paper, its still paper so a physical change has taken place. If you heat or freeze water its only a change of state so its still a physical change. So long as the molecular or chemical structure of the atom/substance does not change it will always be a chemical change. H20 will always be H20.
Breaking, grinding, cracking are all examples of a physical change. The nature of the substance has not changed, just the size of the pieces has changed.
If you mean changing one element into another, like uranium 238 into plutonium 239, which happens in nuclear reactors, the word is 'transmutation'. Otherwise many chemical reactions form new substances, without the elements involved changing, and these would be called 'chemical reactions'.
Vaporization is an endothermic process; evaporation is exothermic.
A science laboratory is a place in which science experiments are taken place.
Changes such as a change in state (solid to liquid), change in color, change in odor, change in solubility, or change in temperature do not provide direct evidence that a chemical reaction has occurred. These changes can be indicative of a physical change rather than a chemical change. To confirm a chemical reaction, additional evidence such as the formation of new substances, evolution of gas, or consumption of reactants is necessary.
Signs that a chemical change has taken place include the formation of a gas, the formation of a precipitate, a change in temperature, and a change in color.
A chemical change has taken place
The change in color indicates that a chemical reaction has taken place.
Physical change.
Fracture formation
A chemical reaction can be determined by observing changes in physical properties, such as color, temperature, gas production, or formation of a precipitate. Additionally, chemical tests or instruments can be used to analyze the substances involved before and after the reaction to confirm a chemical change has taken place.
A chemical change has taken place. The exposure to sunlight causes the paper to undergo a chemical reaction, breaking down the molecules in the paper and causing the color change to occur.
When a hot air balloon flies, the chemical reaction that occurs is the heating of the air inside the balloon, causing it to expand and become less dense than the surrounding air. This creates lift, allowing the balloon to rise. You can confirm that a chemical reaction has taken place by observing the change in volume and buoyancy of the air inside the balloon as it heats up.
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No. If you evaporate the water, the drink powder is left behind. No chemical change has taken place.
Physical. It is a mixture of salt and water. No chemical change has taken place.