Overtime, crusty scales form on the heating coils inside a kettle. these can be removed by covering the coils with vinegar. as the scales disappear, bubbles of gas are observed. does this method of cleaning a kettle represent a physical or chemical change. explain.

Which explanation is true about what happens to a ray of light when it strikes a mirror? a. a light ray is transmitted toward a mirror at a certain angle. the light ray is then reflected by the mirror at an equal angle but in the opposite direction of the transmitted ray. b. an incident ray strikes a mirror at an angle with a line perpendicular to the mirror. the light ray is then reflected at an angle equal to the angle of incidence but on the opposite side of the perpendicular line. c. a reflecting ray strikes a mirror at an angle with a line perpendicular to the mirror. the light ray is then refracted at an angle equal to the angle of the reflecting ray and on the same side of the perpendicular line. d. an incident ray strikes a mirror at an angle with a line parallel to the mirror. the light ray is then transmitted at an angle equal to the angle of incidence but on the opposite side of the parallel line. you so much! : -d take the time to try and answer correctly.

What is the empirical formula of a compound that is 50.7% antimony and 49.3% selenium ?

Select the correct answer from each drop-down menu. to make a table of the elements, dmitri mendeleev sorted the elements according to their . he then split the list of elements into several columns so that elements beside each other had similar .