What are scientific models used for? Give an example of each of the following types of models: Idea, Physical, Compute

How many moles are in 25 grams of H3PO4?

Which of the following explains why elements in column 17 (the halogens) are very reactive?

Hydrochloric acid and sodium hydroxide are mixed together to form salt and water. During the reaction, the temperature of the solution increases. Which of these best explains why this is considered to be a chemical change? A. No energy was destroyed.

Which one of the following statements about orbital energies is incorrect? A) The energy of a given orbital increases as the nuclear charge Z increases. B) In many-electron atoms the energy of an orbital depends on both n and l.

Eutrophication caused by humans is called? a. artificial phosphates b. artificial fertilizer c. artificial trophication d. artificial eutrophication

Which of the following correctly identifies steps used in the fractional distillation of petroleum? The mixture is cooled, condenses, then heated and boils. The mixture is cooled, boils, then heated and condense.

What is the formula of the most stable oxide of francium?

You just calculated that the heat of fusion for chloromethane is 6400 J/mol. The heat of fusion for hydrogen is 120 J/mol. Which of the following account for this difference? a. Hydrogen has stronger intermolecular forces than chloromethane. b.

Magnesium burns with a very bright light. When the flame goes out, a White powder is left behind. what is the word equation for this reaction.

Identify the types of intermolecular forces found for each of the liquids and relate these to the shape of the drop as seen from the side. Include the terms cohesive and adhesive forces properly in your explanations.