OBJECTIVE LIFE SCIENCE
BIOCHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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is always permanent
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involves changing the molecular structure of your reactants
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is changing from one state of matter to another
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none of the above
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Detailed explanation-1: -Physical changes in matter are often reversible: An ice cube can melt into liquid water, and then the liquid water can be frozen back into an ice cube. Chemical changes, on the other hand, are not reversible: A log burned in a fire turns to ashes, but the ashes cannot be changed back into a log.
Detailed explanation-2: -A change of state is a physical change in a matter. They are reversible changes and do not involve any changes in the chemical makeup of the matter. Common changes of the state include melting, freezing, sublimation, deposition, condensation, and vaporization.
Detailed explanation-3: -A physical change is a change to a sample of matter in which some properties of the material change, but the identity of the matter does not. When liquid water is heated, it changes to water vapor. However, even though the physical properties have changed, the molecules are exactly the same as before.