The question is incomplete, here is the complete question.
A chemist prepares a solution of copper(II) fluoride by measuring out 0.0498 g of copper(II) fluoride into a 100.0mL volumetric flask and filling the flask to the mark with water.
Calculate the concentration in mol/L of the chemist's copper(II) fluoride solution. Round your answer to 3 significant digits.
<u>Answer:</u> The concentration of copper fluoride in the solution is 
<u>Explanation:</u>
To calculate the molarity of solute, we use the equation:

We are given:
Given mass of copper (II) fluoride = 0.0498 g
Molar mass of copper (II) fluoride = 101.54 g/mol
Volume of solution = 100.0 mL
Putting values in above equation, we get:

Hence, the concentration of copper fluoride in the solution is 
If 20. 3 grams of an aqueous solution of iron(ii) chloride contains 2. 71 grams of iron(ii) chloride, then percentage by mass of iron(ii) chloride in the solution is 13.34%
Calculation,
Given:
mass of an aqueous solution of iron(ii) chloride = 20. 3 grams
mass of iron(ii) chloride = 2. 71 grams
The percentage by Mass is equal to percentage of mass of solute present in total mass of solution. It is also known as Mass percentage.
percentage by Mass = 100× 2. 71 grams/20. 3 grams = 13.34%
Hence, the percentage by mass of iron(ii) chloride in the solution is 13.34% .
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A change in temperature or color are two signs that a chemical reaction has taken place.
Answer: Physics is about
how things move and why things move
Explanation: