What happens when a catalyst is used in a chemical reaction? a. the reaction rate increases. b. the reaction rate decreases. c. the reaction rate does not change. d. the reaction process decreases.

Consider the nuclear equation below. 239 > x + 4 he 94 2 what is x? 1.235 cm 96 2.243 u 92 3.235 u 92 4.243 cm 96

Identify one disadvantage to each of the following models of electron configuration: -dot structures -arrow and line diagrams -written electron configurations type in your answer below. (answer) -dot structures do not show the distribution of electrons in orbitals and take up a lot of space. -arrow and line diagrams take up a lot of space and make it difficult to count electrons. -written configurations make it easy to lose count of electrons and do not show the distribution of electrons in orbitals.

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?