Question

Need help with question 1

Write the balanced equation for the reaction between malic acid and sodium hydroxide From the balanced reaction, what is the mole to mole ratio of the acid (a) to the base (b). Calculate the moles of malic acid in this experiment. Remember to convert mL to L! moles acid in the Sweet Tarts = (a Times M_b Times V_b)/b Divide the number of moles by the mass in grams of the candy. Report you answer with 3 significant figures and correct unit. Write the balanced equation for the reaction between citric acid and sodium hydroxide From the balanced reaction, what is the mole to mole ratio of the acid (a) to the base (b). Calculate the moles of citric acid in this experiment. Remember to convert mL to L! moles of acid in Smarties = (a Times M_b Times V_b)

Answer 1

Hi, The equation you have is correct. The mole ratio of acid to base is 1:2 since 1 mol of acid reacts with 2 moles of base.

for c, Molarity is given by: $M = \frac{\text{moles}}{\text{Volume in L}}$ so the number of moles of base are given by:

$\text{moles of base} = M_{b} \times V_{b}$

the ratio of acid to base is $\frac{a}{b}$ so the moles of acid are:

$\text{moles of acid} = \frac{a\times M_{b} \times V_{b}}{b}$ I hope you get the idea of where the equation comes from. Now what you have to do it to put the values: a=1, b=2. Mb is the molarity of sodium hydroxide that you have used in the experiment and Vb is the volume that you have transferred in the flask to complete the titration. For example you used 0.1 M NaOH and the volume consumed was 13.2 mL the number of moles of acid would be:

$\text{moles of acid} = \frac{1\times 0.1 M \times 0.0132 L}{2} = 6.6\times10^{-4} mol$

You need to put your own values from the lab experiment.

Now, you have to divide the moles of acid by the mass of candy

suppose you had a 7 grams candy so

$\frac{6.6\times10^{-4} mol}{7 g} = 9.43 \times 10^{-5} \text{mol acid/g candy}$

Hope that helps.