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Is the answer because of the ratio of you fart and the smell in ur nose
Answer: 
Explanation: A double displacement reaction is one in which exchange of ions take place.
The compounds which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
Thus the exchange of ions take place and all the compounds are soluble so the chemical formulas are followed by the symbol (aq).
Number of significant figures will be 1
Given:
weight of acetylsalicylic acid = 0. 4g
To Find:
significant figures
Solution: Significant figures are the digits of value which carry meaning towards the resolution of the measurement. They are also called significant figures in chemistry. All the experimental measurements have some kind of uncertainty associated with them.
When we convert 0.4g acetylsalicylic acid to mg we get value 400mg
when we convert 400mg to gram we get value of 0.4 gram
Since 0 before a decimal is not significant so there is only one significant figure that is 4
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Explanation:
The lack of a control group
This reaction is decomposition. It is the breakdown of a compound into simpler and smaller elements.