The method and the results are on the separating mixtures lab. Do the analysis yourself first, then check the answers below.
Quick answer: To separate a mixture, choose a method that uses a physical difference between its parts. These answers go with the grade 6 science lab on separating mixtures: the graph, the calculations, the uncertainties and the conclusion explained, for all 7 analysis questions.
Use these answers to check your calculations from the sample table. Percentages are worked out from the starting mass, not the final mass. When you suggest a source of loss, name a real step in the method.
Salt (93.3 %). Also, some salt stayed on the glassware and in the damp sand, and some may have spat out of the dish.
Question 4 Why the magnet first?
While the mixture is dry the filings are easy to lift out. In addition, in water the filings would rust and mix with the wet sand, so the magnet comes first.
Question 5 Where is the salt?
The filtrate contains the dissolved salt in water. The salt particles are tiny, so they pass through the paper with the water, so evaporation is needed.
Question 6 Missing mass
30.0 − 28.9 = 1.1 g. Moreover, some of it stuck to glassware and the filter paper, and some salt was left in the damp sand.
Question 7 Improve the lab
Rinse the sand and the beaker with a little more water and add the rinse to the filtrate, so more salt is recovered. This reduces the loss of salt.
