When a substance melts, is energy being added or removed?

An unknown substance has mass of 20 grams and volume of 2 cm3. What is the density of the substance

What distinguishes physical properties from chemical properties

Given the data in the table, what is the average atomic mass of chlorine?

How many joules are absorbed when 86.8 grams of water is heated from 40.0 degrees C to 86.0 degrees C? a) 11,400 joules b) 12,600 joules c) 14,100 joules d) 16,700 joules

How many naturally occurring elements are there

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.