The concentration of hcl can be determined by titration with a primary standard such as na2co3 (sodium carbonate). the titration reaction is co3(2-) + 2h+ > h2o + co2 what is the concentration of hcl if 35.7 ml of hcl was needed to to react with 0.521 g of na2co3 to reach the end point?

The concentration of HCl is 0.275 M

Explanation:

Step 1: Data given

Mass of Na2CO3 = 0.521 grams

Molar mass of Na2CO3 = 105.99 g/mol

Volume of HCl = 35.7 mL

Step 2: The balanced equation:

2HCl + Na2CO3 → 2NaCl + CO2 + H2O

CO3(2-) + 2H+ ---> H2O + CO2

Step 3: Calculate moles of Na2CO3

Moles Na2CO3 = mass Na2CO3 / Molar mass Na2CO3

Moles Na2CO3 = 0.521 grams / 105.99 g/mol

Moles Na2CO3 = 0.0049 moles

Step 4: Calculate moles of HCl

For 1 mol of Na2CO3 consumed, we need 2 moles of HCl

moles of HCL = 2 * 0.0049 = 0.0098 moles HCl

Step 5: Calculate molarity of HCl

Molarity = number of moles of HCl / Volume (liters)

Molarity = 0.0098 moles / 0.0357 L

Molarity = 0.275 M

The concentration of HCl is 0.275 M

answer: they produce more slow than unicellular organisms.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.