Answer:
There are 3 sig figs
Explanation:
Sig figs are the amount of figures counting from the left side of the number until you reach the first zero. Starting from the left, I counted one, three, and six. That's 3 numbers, and therefore, that's how we got our answer. The only exception is when there is a decimal. Then all the numbers before the decimal, despite whether or not they're zeros, are sig figs.
Answer: 8
Explanation: Radon has 8 valence electrons. Radon is considered stable with a complete octet of electrons, filling the s and p orbitals.
.5 mols
Assuming that your 2.0 m is an M for molarity
I used the formula M=number of mold/L
Converted 250mL to .250L by dividing by 1000
Answer:
The percent by mass of 3.55 g NaCl dissolved in 88 g water is 3.88%
Explanation:
When a solute dissolves in a solvent, the mass of the resulting solution is a sum of the mass of the solute and the solvent.
A percentage is a way of expressing a quantity as a fraction of 100. In this case, the percentage by mass of a solution is the number of grams of solute per 100 grams of solution and can be represented mathematically as:

In this way it allows to precisely establish the concentration of solutions and express them in terms of percentages.
In this case:
- mass of solute: 3.55 g
- mass of solution: 3.55 g + 88 g= 91.55 g
Replacing:

Percent by mass= 3.88%
<u><em>The percent by mass of 3.55 g NaCl dissolved in 88 g water is 3.88%</em></u>