Answer:
The signs of chemical change include changes in color, temperature, the production of light, changes in odor, and the formation of gases.
Answer:
Check the electronic configuration of elements.
Explanation:
▪Valence electrons are the elwctrons present in the outermost shell of any element.
For example,
Electronic Configuration of Sodium = 2,8,1
Here , Sodium has 1 valence electrons.
▪Valency of an element is the total no. of electrons to be gained/losed in order to achieve duplet/octate state.
For example,
Electronic configuration of Sodium = 2,8,1
Sodium can achieve octate state either by losing 1 electron or gaining 7 electrons. But losing 1 electron is eay than gaining 7 electrons. So Valency of Sodium = +1
☆Metals have 1 or 2 or 3 valence electrons.
☆Non metals have 4 or 5 or 6 or 7 valence electrons.
☆Noble gases tend to stay in duplet/octate state i.e they have 2 or 8 valence electrons.
Answer:
3Na2SO4
Explanation:
3Na2SO4
# of molecules: 3 moles of Na2SO4 or 3 × 6.22 × 10^23 molecules.
# of elements: 3 elements l
Name of element: = Sodium, S = Sulphur, O = Oxygen
# of atoms: Na = 6 atoms, S= 3, O= 12
Total # of atoms: 21
The #3 is a Coefficient.
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1.05moles
Explanation:
Given parameters:
Number of molecules of C₂H₆ = 6.29 x 10²³molecules
Unknown:
Number of moles = ?
Solution:
The mole is the amount of substances that contains Avogadro's number of particles i.e 6.02 x 10²³
To find the number of moles:
number of moles = 
number of moles = 
number of moles = 1.05moles
Learn more:
moles brainly.com/question/1841136
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