The atomic number of an element is the total number of which particles in the nucleus?

a. neutronsc. electronsb. protons

Which of the following best explains why the atomic theory changed over the past 200 years? The theory was terribly flawed. Few people believed it was correct. The atomic model was incomplete. New experiments led to revised ideas.

During the fall season in North America daylight gradually? A) Increases B) decreases C) lengthens D) brightens

Which equation correctly relates the heat of reaction to the standard heats of formation? ∆H° = ∆Hf ° (products) + ∆Hf ° (reactants) ∆H° + ∆Hf ° (products) = ∆Hf ° (reactants) ∆H° = ∆Hf ° (products) - ∆Hf ° (reactants) ∆H° - ∆Hf ° (reactants) =

The decomposition of HBr (g) into elemental species is found to have a rate constant of 4.2 * 10-3atm s-1. If 2.00 atm of HBr are present initially, how many minutes must elapse to achieve complete conversion into elements (i. e.

Which of the following is an example of a solution? A. An iron alloy B. Iron metal C. An iron ore D. Iron rust

If a sealed syringe that contains some gas in heated in which direction will the syringe plunger move

Use the drop‑down menus to label the statements as either true of false. Dichloromethane is flammable. true false Methanol is flammable. Concentrated sulfuric acid is corrosive. 10% sodium carbonate solution must be used in the fume hood.

What is the process all rocks are continuously in during which that can change into other types of rocks

Collagen is made of fibers and is found in tendons and cartilage. Collagen contributes to meat toughness and is, therefore, an example of which type of protein?

1. Why does CH30 evaporate faster than water?