A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity.

Examples of chemical changes are burning, cooking, rusting, and rotting.

Examples of physical changes are boiling, melting, freezing, and shredding.

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3 years ago

Draw the Lewis structure for the Se and 2 H atoms.

fomenos

When drawing lewis dot diagram structure we consider the number of valence electrons of the atom.Se has six valence electrons since it is in group six thus it Lewis dot diagram is as follows
..
: Se:
Hydrogen is in group one hence has one valence electron.The lewis dot diagram for 2H is therefore
H:H

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3 years ago

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What is measured by the reaction rate? the probability that a reaction will occur the speed at which products form the time requ

Cloud [144]

Answer: the speed at which products form

Explanation:

Rate of a reaction is defined as the speed at which a chemical reaction proceeds. It is often expressed in terms of the concentration of a reactant that is consumed in a unit time or the concentration of a product that is formed in a unit of time.

For a general reaction : $A\rightarrow B$

$Rate=-\frac{d[A]}{dt}$

or $Rate=+\frac{d[B]}{dt}$

where d[A] = change in concentration of reactant A

d[B] = change in concentration of product B

dt = time interval

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3 years ago