1. Tiffany's class did an experiment to prepare a compound by reacting copper and sulfur. The following is the account of Tiffany's experiment. I weighed some coppet powder and added excess sulfur powder to it. After mixing, a yellow-brown mixture was formed. I heated the mixture in a test tube. It glowed red-hot. A blue-grey solid was formed. I removed the excess sulfur with xylene and obtained the blue-grey solid left behind. (a) Tiffany has left out the details of how she removed the excess sulfur. Describe the procedure she should have used. (Hint: Only sulfur is soluble in xylene.)

Earth's axis of rotation is tilted at an angle of 23.5 degrees. what is one change you would see on earth if its axis was not tilted?

Plz me ! 1 which of earths spheres contains most of its mass? a atmosphere b hydrosphere c geosphere* d biosphere 2 erosion and weathering are examples of which types of forces? a constructive forces b destructive forces* c gravitational forces d inertia-related forces 3 which of the following statements about earths atmosphere is true? a earths atmosphere contains 78% water vapor which is essentail to life b earths atmosphere contains 21% oxygen c earths atmosphere contains carbon dioxide which all life forms require d earths atmosphere allows radiation from the sun to pass through it and warm earths surface* 4 the strenght of the force of gravity between two objects is determined by which of the following factors? select all that apply a the messes of the objects* b the distance between the objects* c the volumes of the objects d the surface area of the objects 5 earth and moon are kept in there respective orbits due to the influence of a inertia b gravity c gravity and inertia* d neither gravity or inertia if you answer all questions right i will give

Which of the following nuclei would be the least stable a 2 protons, 2 neutrons b 1 proton 1 neutron c 1 proton 3 neutrons d 1 proton 2 neutrons