A student attempted to identify an unknown compound by the method described in this experiment. When...

A student attempted to identify an unknown compound by the method described in this experiment. When he heated a sample weighing 1.031 g the mass went down to 0.688 g. When the product was converted to a chloride the mass went up to 0.748 g. (Answers I got are in bold)

1.Explain if you believe the sample to be a carbonate or hydrogen carbonate. (I said it is a hydrogen carbonate due to the loss of mass)

2.Write the two possible chemical equations for the reaction that that you believe occurred; one for sodium and one for potassium (carbonate or hydrogen carbonate). (we are supposed to use these two formulas but I am not sure how: 2XHCO3→ X2CO3 + H2O + CO2 this is hydrogen carbonate X2CO3 + 2 H+ + 2 Cl-→ 2 XCl + H2O + CO2 This one is for the hydrochloric acid being added)

3.Show by calculation how many moles of the chloride salt would be produced from one mole of original compound; one for sodium and one for potassium (carbonate or hydrogen carbonate).

4.Fill out the following information to help you determine how many grams of the chloride salt would be produced from one molar mass of original compound?

If NaHCO3 ____________ g original compound → ____________ g chloride

If KHCO3 ____________ g original compound → ____________ g chloride

If Na2CO3 ____________ g original compound → ____________ g chloride

If K2CO3 ____________ g original compound → ____________ g chloride

5.Calculate the theoretical value of Q for all 4 compounds

6.What was the student’s observed value of Q? ( I got 1.378 since this is calculated by original mass divided by final mass)

7.Which compound did the student have as their unknown?

Solutions

Expert Solution

queen_honey_blossom answered 1 year ago

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