Which of the following is evidence of a chemical change?

phase change

the formation of a gas

mass change

change in surface area

A student heats a test tube containing a large amount of protien and biuret reagent. She notices a color change from violet to blue. Explain why.

What is the formula for copper (II) phosphate? Capitalization and punctuation count. How many atoms of phosphorus are in 7.10 mol of copper (II) phosphate?

Where does most of the mass of an atom exist?

A student has 5 mL of 0.300 M (NH4) 2CrO4 solution. What is the concentration of NH4 + in this solution?

Mole is taken in units of gram-mole. on this basis, how many atoms are there in a pound-mole of a substance?

If something is in high resolution you can see and object but not very clearly. True or False.

Which change might cause a cold spell in the northern united states

Kipps appratus is for what?

Which of the following statements about protons are true? Protons have twice the mass of neutrons. Protons have the same magnitude of charge as electrons but are opposite in sign. Protons have a charge of 1+.

What is true of an acidic solution at room temperature?