Read through the whole method before starting any practical work. Where appropriate, prepare a table for your results in the space provided. Show the precision of the apparatus you used in the data in record. Show your working and appropriate significant figures in the final answer to each step of your calculations. 1 In this experiment you will determine the relative atomic mass, A,, of metal M by thermal decomposition of its basic carbonate, MCO3•M(OH)2. FB 1 is the basic metal carbonate, MCO3•M(OH)2.

1. (a)Method • Weigh the empty crucible with its lid. Record the mass. • Transfer all of the FB 1 from the container into the crucible. • Weigh the crucible, lid and FB 1. Record the mass. • Calculate and record the mass of FB 1 used. • Place the crucible and contents on a pipe-clay triangle. • Heat the crucible gently, with the lid on, for approximately 1 minute. • Heat strongly, with the lid off, for a further 4 minutes. • Replace the lid and leave the crucible to cool for at least 5 minutes. During the cooling period, you may wish to begin work on Question 3. • When the crucible is cool, weigh the crucible with its lid and contents. Record the mass. • Place the crucible and contents on the pipe-clay triangle. Remove the lid. • Heat the crucible strongly for a further 2 minutes. • Replace the lid and leave the crucible to cool for at least 5 minutes. • When the crucible is cool, reweigh the crucible with its lid and contents. Record the mass. • Calculate and record the mass of residue obtained. Results I II III IV V[5]
2. (b)(i)When FB 1 undergoes thermal decomposition, the products are the metal oxide, MO, carbon dioxide and water vapour. Give the equation for the thermal decomposition of FB 1. Include state symbols.[1]
3. (b)(ii)The amount, in mol, of carbon dioxide produced is given by the following formula. amount of CO2 = mass loss during heating / (Mr of CO2 + Mr of water) Calculate the amount, in mol, of carbon dioxide produced in (a).[1]
4. (b)(iii)Calculate the relative formula mass, Mr, of the basic metal carbonate. Show your working.[1]
5. (b)(iv)Calculate the relative atomic mass of metal M.[1]
6. (c)A student accidentally spilt a little of the residue before carrying out the final weighing. Predict whether the calculated value of the relative atomic mass of M will be higher or lower as a result of this mistake. Explain your answer.[1]
7. (d)A student suggested that addition of sulfuric acid to the residue from (a) would show whether the basic metal carbonate had decomposed fully. State whether the student is correct. Explain your answer.[1]