Amixture is a physical combination of two or more different substances, regardless of how much you have of each. mixtures can be separated using physical means. that is, chemical reactions are not necessary to separate the different mixed-up components. for example, let’s say you have a mixture of 100 iron-rich magnetic particles and 100 grains of table salt. come up with at least three different ways to separate the particles and grains. hint: think of some of the physical properties of these substances.

Neils bohr believed that electrons orbited the nucleus in different energy levels, based on strong support from

Agroup of students is studying convection current. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other is in an area with warm air. after 10 minutes, the balloon are released from a height of 1 meter. which of the following to the students most likely observe? a) the warm balloon expands and rises. the cold balloon shrinks and sinks b) the balloon both rise. the cold balloon is larger than the warm balloon c) the cold balloon expands and rises. the warm balloon shrinks and sinks d) the balloon rise at the same rate. both balloons are the same size

Areaction in which products can react to re-form reactants is