Answer:
Explanation:
Physical Change:
The changes that occur only due to change in shape or form but their chemical or internal composition remain unchanged.
These changes were reversible.
They have same chemical property.
These changes can be observed with naked eye.
Example
:
Water converting to Ice
Water converting to gas
In this water molecule remain the same only they rearrange themselves that change its state of mater not composition
Chemical changes:
The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.
These changes are irreversible
These changes occur due to chemical reactions
These may not be observed with naked eye
Example:
Combustion of fuel or wood: that oil or wood convert into energy, CO₂ and ash in case of wood
Boiling of egg: that change the chemical composition of protein in the egg
The reaction of Hydrogen and oxygen:
H₂ (g) + O₂ (g) -------------------------------------> 2H₂O (l)
<u>True,</u> A mole of one substance has the same number of atoms as a mole of any other substance.
<h3>
What is a mole?</h3>
Mole, also spelled mol, in chemistry, a standard scientific unit for measuring large quantities of very small entities such as atoms, molecules, or other specified particles.
The mole designates an extremely large number of units, 6.02214076 × . The General Conference on Weights and Measures defined the mole as this number for the International System of Units (SI) effective from May 20, 2019. The mole was previously defined as the number of atoms determined experimentally to be found in 12 grams of carbon-12.
The number of units in a mole also bears the name Avogadro’s number, or Avogadro’s constant, in honour of the Italian physicist Amedeo Avogadro (1776–1856). Avogadro proposed that equal volumes of gases under the same conditions contain the same number of molecules, a hypothesis that proved useful in determining atomic and molecular weights and which led to the concept of the mole.
Learn more about mole
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Uhhhhhhhhhhhhhh wut, can you rewrite it?
The Permian-Triassic extinction event<span> about 250 million years ago was the deadliest: More than 90 percent of all species perished. Many scientists believe an asteroid or comet triggered the massive die-off, but, again, no crater has been found. Another strong contender is flood volcanism from the Siberian Traps, a large igneous province in Russia. Impact-triggered volcanism is yet another possibility.</span>
Answer:
HowHow many moles of KOH are in 21.0g of KOH?