Answer: 
is the correct equation for beta decay.
Explanation:
When a beta particle, that is, 
is emitted in a radioactive decay then it is known as beta decay.
Therefore, beta decay of Polonium-218 is as follows.
Therefore, we can conclude that is the correct equation for the given beta decay.
Answer:
Hard-boiled eggs can be preserved up to 7 days in the refrigerator.
Explanation:
Answer:
No, IR should not soely be used to identify molecules
Explanation:
IR is a method that identifies the functional groups in a molecule by deducing the frequency of stretching and vibration of bonds. Each peculiar type of bond has a frequency for the vibration of each bond represented on the IR spectrum.
However, one method is never enough to identify a compound. A combination of methods must always be used to clear up ambiguities arising from overlapping IR frequencies. Also, interpretation of the nuanced peaks of the fingerprint region in IR spectra is quite challenging and only gives a fair idea of the functional groups present in the compound.
Therefore other methods such as NMR, UV-VISIBLE etc should also be involved in the identification of compounds.
<span>Answer: a mixture.
</span><span>Justification:</span>
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</span><span>1) Pure substances have a definite chemical formula: the same kind of atoms with the same fixed ratios and chemical bonds. Therefore, the percents of each element do not varye.
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2) Elements and compounds are pure substaces. For example, Fe, Mg, Ti, are elements, and CO₂, CO, H₂CO₃ are compounds. Each of them will have always the same kind of atoms, in the same ratio and with the same chemcial bonds. Therefore the percents of the elements do not varye.
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<span>3) Mixtures are formed by the physical combination (not chemical bonds) of different elements or compounds in variable proportions. As indicated, this describes the material bronze, in virtue of the variation of its composition. Other examples of mixtures are solutions (like brines), air, ocean water, and milk: different brines, different oceans and different milk have different contents of elements or compounds.
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