Which of these ions has the largest radius (Se2-, Br-, Rb+, or Sr2+ )? 

A 36.0 g sample of an unknown metal is heated from 25oC to 35oC and 171.7 J of heat is absorbed. Use the chart below to identify the unknown metal.  

Which of the following statement(s) is/are correct  Sample A can be a representation of a flask containing sulfur dioxide gas. Sample B can be a representation of a flask containing carbon monoxide gas. Sample C can be a representation of a flask containing helium gas and hydrogen gas. 

Which of the following statement(s) is/are correct?   Ag is the symbol for silver H is the symbol for hydrogen S is the symbol for sodium 

Choose the correct name for NiS2. 

The following image shows interactions between molecules of ethylamines (CH3CH2NH2). From the image identify the hydrogen bonds. 

Which of the following gases have the greatest root mean square velocity/speed?

Which of these ions has the largest radius (O2-, F-, Na+, or Mg2+)?

Using the data below on successive ionization energies, determine what the element could be?    Number of Electrons Removed  Ionization Energies (kJ/mol)   1  600  2  1200  3  3000  4  12,000  5  13,000  6  14,500  7  15,600 

Determine the amount of heat released (in kilojoules) when 12.20 grams of ethane, C2H6, undergoes combustion according to the following equation: 2C2H6 (g) + 7O2 (g)