Answer is: key
design change for HFC-134a A/C systems versus CFC-12 A/C systems was quick
couple service fitting and that design reduce venting and mixing of
refrigerants during service.
<span>
Level of contamination is also reduced
and the emission of refrigerants and greenhouse gases (sulfur
dioxide, carbon dioxide) is also reduced.</span>
After 25 days, it remains radon 5.9x10^5 atoms.
Half-life is the time required for a quantity (in this example number of radioactive radon) to reduce to half its initial value.
N(Ra) = 5.7×10^7; initial number of radon atoms
t1/2(Ra) = 3.8 days; the half-life of the radon is 3.8 days
n = 25 days / 3.8 days
n = 6.58; number of half-lifes of radon
N1(Ra) = N(Ra) x (1/2)^n
N1(Ra) = 5.7×10^7 x (1/2)^6.58
N1(Ra) = 5.9x10^5; number of radon atoms after 25 days
The half-life is independent of initial concentration (size of the sample).
More about half-life: brainly.com/question/1160651
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The process that is being shown by water being given off from a bond site is DEHYDRATION SYNTHESIS.
Dehydration synthesis is the process of joining two molecules or compounds together as a result of removal of water.
Answer: The density of the object will be 
Explanation:
Density is defined as the mass contained per unit volume.

Given : Mass of object = 19.6 grams
Volume of object= 
Putting in the values we get:

Thus density of the object will be 
Answer:
I think B
Explanation:
There are more negative ions than positive ions