When energy is added or removed, is it a physical change, a chemical change, or both?

The atoms of a metalloid have 6 valence electrons. The metalloids is used as a semiconductor. Which best describes the electron shell in which the valence electrons are located

You are conducting a weathering study and your solution analysis indicates that you have 1.8 X 10-3 M silica and a pH of 3. You plug this data into your chemical speciation computer program and indicates that quartz precipitates.

2.15g of an unknown gas at 51c and 1.00 atm is stored in a 2.95 L flask

The distance from the trough of one wave to the trough have another wave is wave amplitude True or false

you go out to dinner and the bill comes to $35.51. how much should you tip if you want the tip to be 20% of the bill.

Limes have a [H3O+] of 1.3 x 10-2 mol/L. Their pOH is

The human body is 0.0040% iron. How many milligrams of iron does a 165 pound person contain?

Which of the following is the correct Lewis structure for ammonia (NH3) ? Note: Hydrogen and nitrogen have one and five valence electrons respectively.

Which of the following statements is true? A. Particles of a solid have a very orderly, three dimensional arrangement and do not move B. Particles of a liquid change shape and volume C.

How does hess's law use intermediate reactions to calculate the enthalpy of a desired reaction?