Which of the following changes has a decrease in entropy? A. N2O4 (g) yields 2NO2 (g)

B. C2H5OH (l) + 3O2 (g) yields 2CO2 (g) + 3H2O (g)

C. 3O2 (g) + 2KCl (s) yields 2KClO3 (s)

D. H2O (l) yields H2O (g)

Define the following terms. a. law of conservation of mass

Multiple Choice A scientist performs an experiment on an unknown element. She finds that the unknown element forms an ionic bond with beryllium (Be). She concludes that the unknown element must belong in group 2 of the periodic table.

Which two of these are chemical reactions? Tick two boxes. You dissolve a spoonful of sugar in water. Bread goes brown in the toaster. You take an ice lolly out of the freezer and it strats to melt. Frost forms on the grass an a cold night.

What most likely caused the water to rise in and erupt from the vent

You can become an unsafe driver at BAC levels of what

The spines and thick wavy cuticle on a cactus are both what

What type of chemical process is used to create perfume?

Which of the following is a polyatomic ion? O A. HCI O B. Na O C. PO, O D. 52

What are the cations and anions for V2 (CO3) 3

If you were asked to convert 4.2 x 1022 atoms of aluminum to moles, which of the following should you use for the conversion?