The answer to this question would be: 3.125%
Half-life is the time needed for a radioactive molecule to decay half of its mass. In this case, the strontium-89 is already gone past 5 half lives. Then, the percentage of the mass left after 5 half-lives should be:
100%*(1/2^5)= 100%/32=3..125%
A Chemical change is any form of chemical reaction changing the state of the matter involved. When you fry an egg, you are making a reaction between the heat and the chemicals that make up the egg. Therefore once you have fried that egg, you have completed a chemical reaction. This is why it's a chemical change when you fry an egg.
The statement that describes what makes a base weak is that the base will be unable to dissociate completely in water.
<h3>What is a base?</h3>
A base is any of a class of generally water-soluble compounds, having bitter taste, that turn red litmus blue, and react with acids to form salts.
Bases usually dissociate into hydroxide ions (OH-) when in an aqueous solution.
However, a base is termed weak or strong depending on it's ability to dissociate completely. A weak base does not dissociate completely into hydroxide ions when in an aqueous solution.
Learn more about bases at: brainly.com/question/23687757
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The correct answer is
D burning wood
because it's changing the wood.
The other's are physical changes because it's still the same thing, it's just in a different form.
Glad I could help, and good luck!
AnonymousGiantsFan