A small cup of water is left out on the counter. Three days later, the water is gone. Which phase change describes what has occurred?

Melting

Sublimation

Evaporation

Condensation

The electron configuration below represents what element? 1s22s22p63s23p64s2

What is emitted during gamma radiation?

How many photons are produced in a laser pulse of 0.682 J at 649 nm?

A pure substance is found to be a good conductor of electricity in both its solid and liquid phases. The bonding in the substance is which one of the following? (a) ionic (b) covalent molecular (c) metallic (d) covalent network

A mixture is made of 3.35 g of SiO2, 0.38 g of cellulose and 8.76 g of calcium carbonate. What is the percent of cellulose in the sample?

For the baeyer-villiger oxidation of cyclohexyl methyl ketone

What will happen if the density of an object is less than the density of water?

Which cannot be separated into simpler substances? compound element solution mixture

What jobs involve chesmistry

Think about a neutral magnesium atom. Then think of a magnesium ion with a 2+charge. How are these two alike? How are they different? Be sure to use the terms proton, neutron, and electron in your answer.