The experiment was repeated with 25 cm of 0.2 mol/dm sodium thiosulfate and 25 cm of water. a Typical results for this experiment and a further two experiments are given in the table. Experiment 2 3 4 1 Volume of thiosulfate/cm3 50 10 40 25 Volume of water/cm 0 10 25 40 Volume of acid / cm 5 5 5 5 07 Total volume/cm’ 55 55 55 55 Time/s 48 60 96

Write the symbol for every chemical element that has atomic number greater than 3 and atomic mass less than 12.0 u.

One similarity and one difference between an element and a mixture of elements

How does a sample of helium at 15 degree celsius compare to a sample of helium at 215 k? a) the helium at 15 degrees celsius has a higher average kinetic energy that the sample at 215 k. b) the helium at 15 degrees celsius has lower nuclear energy that the sample at 215 k. c) the helium at 15 degrees celsius has slower- moving atoms that the sample at 215 k. d) the helium at 15 degrees celsius has smaller atoms than the sample at 215 k.