Author: Anonymous

Below is an isotope notation of element A. Determine the number of protons, neutrons, and identify the element.   Protons Neutron Element A 29 65 Copper (Cu) B 36 29 Krypton (Kr) C 36 65 Krypton (Kr) D 65 29 Terbium (Tb) E 29 36 Copper (Cu)

 What is the limiting reagent, excess reagent, and theoretical yield for the following reaction if the starting amount of X2and A2 are provided in the image labeled starting amounts before reaction below?

Using the image below to determine which of the following statements is/are true.  Substance A represents molecular compounds Substance B represent molecular compounds Substance C represents atoms of an element

Ethanol (C2H5OH) burns in oxygen to produce carbon dioxide and water. Balance the equation for this reaction using small, whole numbers. What is the coefficient of ethanol in the balanced equation? __C2H5OH  +  __ O2 

The graph represents how the potential energy changes with respect to two species interacting. Determine which of the following statements are true about the graph below. The graph shows electrostatic attraction The graph shows electrostatic repulsion The two species have charges of the same sign.

Part A. On the axes below, sketch and label a graph (including the axes) showing how the potential energy changes as two helium atoms (He) approach each other. Use a solid line for He. Part B. Now using the same graph from Part A use a dotted line —— to show how the potential energy changes when two nitrogen atoms approach each other to interact.    Part C. On the graph above for Parts A and B, using an arrow, clearly indicate the position where the system is most stable for each curve (helium and nitrogen).   Part D. For each of the positions in Part C that you indicated, please draw what the system would look like on the molecular level at that point. Be sure to label any interactions and/or covalent bonds that may exist at this position for the system. Part E. Using your answers from Parts A-D, explain why there is a difference between the two systems with respect to each axis. Make sure to include interactions and energy in your answer where appropriate. Differences for x-axis:   Difference for y-axis:      

Using the image below to determine which of the following statements is/are true. Substance A represents molecular compounds Substance B represents atoms of an element Substance C represents molecular compounds 

Which statement is true about 10.0 g of nitrogen gas (N2) and 10.0 g of water (H2O)?

Free Response 1  The element krypton (Kr) is used in lighting, photography, and fluorescent lamps. Kr has a melting point of -157 oC and boiling point of -153 o Part A. Please show Kr and its interactions at -155 oC and -50 oC.  Please label all interactions (ie. London dispersion forces and/or covalent bonds) at each temperature and label the states of matter. Be sure to include a key. Part B. Please explain, using your understanding of forces and energy, what is happening on the molecular level as Kr is heated from –155 oC to -50 oC as shown in Part A.  (Use 1-2 sentences)

The graph represents how the potential energy changes with respect to two species interacting. Determine which of the following statements are true about the graph below. The two species have charges of the same sign. The graph shows electrostatic repulsion The graph shows electrostatic attraction