How many molecules are there in 0.250 moles of sodium hydroxide

How many molecules of ammonia are present in 3.0 g of ammonia (Formula = NH3) ? A) 1.2 * 1024 B) 1.8 * 101 C) 1.1 * 1023 D) 2.9 * 10-25 E) 3.6 * 1023

What type of reaction is shown below? 2Na + 2H2O?2NaOH + H2 + heat A. nuclear B. exothermic C. endothermic D. spontaneous

Which factor would slow down a chemical reaction? (Choose all that apply) A) Adding an inhibitor B) Decreasing temperature C) Decreasing particle size D) Increasing particle size

Why doesnt the number of neutrons identify an element

What is the pH of a 2.0 M solution of HClO4?

Calculate the percent yield when 500 grams of carbon dioxide react with an excess of water to produce 640 grams of carbonic acid. CO2 + H2O - --> H2CO3

Which of the following is a possible equivalence that can be used in a conversion? A. ten to the negative second power hL over one L B. ten to the negative second power cL over one L C. ten to the first power L over one daL D.

Which process is a chemical change? burning a match boiling water melting ice breaking glass

What form of matter is "vapor"? a. a solid made of a substance that is usually liquid c. a gas made of a substance that is usually solid b. a liquid made of a substance that is usually gas d. a gas made of a substance that is usually liquid

Which of the following atoms releases more energy than oxygen when an electron is added to its valence energy level? Select one: a. helium (He) b. fluorine (F) c. carbon (C) d. nitrogen (N)