In a beaker, sugar is dissolved in water, and then the water is heated and evaporates. the sugar is recovered, and heat is again applied. vapor is released, and the material in the beaker changes from white to black. what must you know to determine if a chemical change occurred? a) the boiling point of water b) the boiling point of sugar c) the identity of the black substance d) temperature at which sugar evaporates

If a polyatomic ionic compound has gained two hydrogen ions, then how does its name begin?

Fossil fuels are organic compounds that are made from

Electromagnets coils of wire paper clips picked up 10 3 15 6 20 9 25 12 ms. owens' class was studying magnets. ms. owens showed her students how to make an electromagnet using a nail, a d-cell battery, and plastic coated wire. the students wrapped the wire around the nail and then attached the ends to the battery. when they were finished, they tested their magnets by investigating how many paperclips their magnets could pick up. they also tested whether they could increase the strength of their electromagnets by using more coils of wire. they recorded the class average of their results in the data table seen here. ms. owens asked her students to graph their data in a line graph. how should the students label the x-axis on their line graph? a) size of battery b) number of paper clips c) number of coils of wire d) strength of electromagnet