The gram-formula mass of citric acid is 3(1)+6(12)+5(1)+16(7)=192 g/mol.
This means that in 13.00 grams of citric acid, there are 13.00/192 = 0.067 moles.
From the equation, we know that for every 1 mole of citric acid that is consumed, 3 moles of carbon dioxide are produced.
This means that there are 3(0.067)=0.203 moles.
Since the gram-formula mass of carbon dioxide is 12+2(16)=44 g/mol, meaning it has a mass of 0.203(44)=8.93 g
The question is incomplete, here is the complete question:
A chemist makes 600. mL of magnesium fluoride working solution by adding distilled water to 230. mL of a stock solution of 0.00154 mol/L magnesium fluoride in water. Calculate the concentration of the chemist's working solution. Round your answer to 3 significant digits.
<u>Answer:</u> The concentration of chemist's working solution is 
<u>Explanation:</u>
To calculate the molarity of the diluted solution (chemist's working solution), we use the equation:

where,
are the molarity and volume of the stock magnesium fluoride solution
are the molarity and volume of chemist's magnesium fluoride solution
We are given:

Putting values in above equation, we get:

Hence, the concentration of chemist's working solution is 
Reduction reactions are those reactions that reduce the oxidation number of a substance. Hence, the product side of the reaction must contain excess electrons. The opposite is true for oxidation reactions. When you want to determine the potential difference expressed in volts between the cathode and anode, the equation would be: E,reduction - E,oxidation.
To cancel out the electrons, the e- in the reactions must be in opposite sides. To do this, you reverse the equation with the negative E0, then replacing it with the opposite sign.
Pb(s) --> Pb2+ +2e- E0 = +0.13 V
Ag+ + e- ---> Ag E0 = +0.80 V
Adding up the E0's would yield an overall electric cell potential of +0.93 V.
The answer is 2 15 12 6
hope this would help you