Chemical change: a reaction/event where the chemicals/elements present before the change are NOT the same molecules present after the change.
For example, combustion reactions such as the burning of wood or rubbing alcohol are examples of chemical change. The reactants before the combustion of rubbing alcohol are CH3O (rubbing alcohol) and O2 oxygen (oxygen). The molecules present after the combustion reaction are CO2 (carbon dioxide) and H2O (water vapor).
Physical Change: a change in structure or state of a substance but, after the change the material is the same material that we started with. One example would be breaking a glass bottle by dropping it. The glass is now in smaller pieces than when we started, but the glass molecules are still glass molecules.
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Friction but i may be wrong
Answer:
Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of ions. The results are typically presented as a mass spectrum, a plot of intensity as a function of the mass-to-charge ratio.
Explanation:
Tip your bucket into a mass spectrometer. It turns the atoms into ions Then it will separate the ions by passing them first through an electric field, then through a magnetic field, so they fan out into a spectrum
Answer:
Substances can change phase — often because of a temperature change. At low temperatures, most substances are solid; as the temperature increases, they become liquid; at higher temperatures still, they become gaseous.
Explanation:
Answer:
Distance covered by Joe, d = 5 km
Explanation:
It is given that,
Speed of Joe, v = 20 km/hour
Time taken by Joe, t = 15 minutes = 0.25 h
We need to find the distance he is covering. It can be calculated using definition of speed as :
d = 5 km
So, Joe covers a distance of 5 km. Hence, this is the required solution.
