A) Double replacement
Because the reactants switch when they become products
Answer:
Noble Gases are very stable because...
1) Noble Gases have a full octet
2) Low chemical reactivity
Explanation:
This means that is has 8 valence electrons so it won't need any more, so it is less likely to react with other substances.
The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
Answer:
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Answer:
Explanation:
True or false 4 questions help please!
Most mixtures are not physical changes.
True
False FALSE when I add solid NaCl salt to water I no longer have a solid salt, I have a solution of sodium and chlorid ions in liquid water. this is physical change
Chemical Changes do not create a new substance.
True
False FALSE 0ne of the proofs that you have a chemical change is the presence of a new substance
Fire is an example of a Chemical Change.
True TRUE fire is oxygen reacting wiIh mattter to form new compounds
False
Explosions are not chemical changes.
It depends on the explosion if I blow up a balloon until it POPS!! that is physical chame. If I light a firecracker and it explodes, that is a chemical change of oxygen reacting with hot gunpowder
A change in color and odor are both examples of chemical changi
I would rewrite the question as
A change in color and odor both INDICATE a chemical change
and that is
True TRUE
False
F
True Fire is an example of a Chemical Change.
True
False
Explosions are not chemical changes.
True
False
