0
Change in temperature is usually an easy way - most reactions give out or take in a little heat when they occur - very few will have a change too small to measure or too slow evolution of heat to effectively measure. Changes in temperature can however also occur from a physical change such as dissolution of a salt in water. In these cases you're often looking for a change such as a solid material precipitating from a solution, a colour change, evolution of a gas or change in pH. These are common quick and dirty ways to know if a chemical change is likely to have occurred. The absolute ways are to test the reaction afterwards by spectroscopic methods or chromatographic methods and compare these to time zero before reation could have started.
What else can I help you with?
What sensory evidence could be used to argue that a chemical transformation of a substance had occurred?
Sensory evidence of chemical reactions may be: - Change of color - Change of odor - Change of aspect - Change of the temperature - A violent reaction with explosion or fire - Bubbling - Emitting a sound - Emitting a light
What observations does not indicate that a chemical change has occurred a. change of state b. formation of a precipitate c. absorption of energy d. release of a gas?
Change of state does not necessarily indicate a chemical change. It could be a physical change, such as melting or freezing, where the substance remains the same chemically. On the other hand, the formation of a precipitate, absorption of energy, and release of a gas are all indicators that a chemical change has occurred.
How could one determine whether a sample of aspirin is pure or not?
The determination is by chemical analysis.
What slowly change earth crust?
Weathering, chemical change, and mechanical change. I hope i could help.
When you mix a pink powdered substance in water and mix it is that a chemical change?
Mixing is not itself a chemical change. There could be one occurring as a result, but nothing you described indicated any kind of chemical change.
What sensory evidence could be used to argue that a chemical transformation of the substance had occurred?
by a change in smell and appearence of a substance
Which observation does not indicate that a chemical reaction has occured?
A change in state, such as boiling or melting, does not always indicate a chemical reaction has occurred. It could be a physical change.
What sensory evidence could be used to argue that a chemical transformation of a substance had occurred?
Sensory evidence of chemical reactions may be: - Change of color - Change of odor - Change of aspect - Change of the temperature - A violent reaction with explosion or fire - Bubbling - Emitting a sound - Emitting a light
How could you determine if precipation had occurred?
i don't know
What observations does not indicate that a chemical change has occurred a. change of state b. formation of a precipitate c. absorption of energy d. release of a gas?
Change of state does not necessarily indicate a chemical change. It could be a physical change, such as melting or freezing, where the substance remains the same chemically. On the other hand, the formation of a precipitate, absorption of energy, and release of a gas are all indicators that a chemical change has occurred.
How might a thermometer help you decide if there was any chemical change on mixing iron and charcoal?
For a chemical change to occur, there must be a chemical reaction. A chemical reaction would be either endothermic (uses energy, mostly heat), or exothermic (produces energy, again mostly heat). Any change in temperature of the reactants, as measured by a thermometer, will tell you not only ifa chemical reaction occurred, but also which kind of chemical reaction. No temperature change usually indicates that no reaction has occurred, a decrease in temperature would indicate an endothermic reaction, while an increase in temperature would indicate an exothermic reaction.
Is tarnisha physical change or chemical change?
Well it could either be a physical change OR a chemical change. .
Could the identity stay the same in chemical change?
No. If one substance does not change into another, it is not a chemical change.
If two chemicals are added together in a beaker and the beaker gets cold is that a chemical reaction?
Not necessarily. The cooling effect could also arise from mixing chemicals that absorb heat when mixed with each other, even though they do not react. The cooling could, of course, also indicate a chemical reaction.
How can you tell that the melting of ice cube is a physical change?
You could test the resulting liquid by determining its boiling point and melting point. If they are the same as the boiling and melting points for water, then it is probably water and a physical change rather than a chemical change has occurred.
How could you test whether a chemical or physical reaction occurred?
Signs of chemical reactions may be: - Gas release - Formation of a precipitate - Change of color - Change of odor - Change of pH - Change of aspect - Change of viscosity - Change of the temperature - Visible formation of new compounds - Change of the state of the matter - A violent reaction with explosion or fire - Bubbling - Emitting a sound - Emitting a light----------------------------------------------------------------During a physical change the molecule composition is not affected.
What change could happen during a chemical reaction?
the chemical shall be changed
