<span>Balanced chemial equation:
2NaI(aq)+Hg2(NO3)2(aq) →Hg2 I2 (s) + 2 NaNO3 (aq)
You can see it better if I use latex:

As per the phases this is the interpretation:
The symbols (aq) stands for aquous meaning that the compound is dissolved in water.
The symbol (s) stands for solid, meaning tha the compound precipitate and is not dissolved in water.</span><span>
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Answer: the mass number of an element is equal to the number of protons plus the number of neutrons.
Hello!
Percentage error = (true value - measured value)/true value x 100%
Percentage error = (27.7-27.0)/27.7 x100% = 25.3%
Answer:
7.941
Explanation:
You can look at a picture of the periodic table.To calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons. Example: Find the atomic mass of an isotope of carbon that has 7 neutrons. You can see from the periodic table that carbon has an atomic number of 6, which is its number of protons.
Hope I helped