Which of the following is a physical change?

explosion

rotting of food

evaporation

rusting of iron

What is the final concentration, in mg/mL, for a solution prepared by adding 12.00 mL of a 3.590 mg/mL Cu2 + stock solution into 100.00 mL volumetric flask and filled with water to the calibration mark?

What does algebra mean

Contrast solid nonmetals and solid metals.

The type of bond between atoms of potassium and chloride in a crystal of potassium chloride a. hydrogen bond b. ionic bond c. polar covalent bond d. pure covalent bond e. metallic bond

Never trust Wikipedia .

Andy has two samples of liquids. Sample A has pH of 4, and sample B has a pH of 6. what can Andy conclude about these two samples? Sample A is a neutral b alkali c acidic Sample B is a neutral b alkali c acidic

How does a lone pair contribute to molecular shape? A. It is too small to affect the molecule's shape. B. It takes up space like an "invisible" atom. C. It forces the molecule into a tetrahedral shape. D. It lets the bonding pairs spread out more.

The are of a rectangle is 12 in^2. what is the area in cm^2. there are 2.54cm in an inch.

Which statements describe advantages of models? Check all that apply. Models make it possible to easily notice patterns. Models can be used to communicate and test design ideas. Models allow scientists to predict relationships.

Are energy levels and orbitals the same thing?