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Element A has a molar mass of 12.50 g/mol.  Element B has a molar mass of 15.25 g/mol.  They make a compound, AB2. Please calculate the % by mass for Element A and the % by mass for Element B. Type in your work below.

Given 22889 Ra  –>  22890 Th  +  ____.  What type of nuclear radiation is demonstrated?

Consider the following system at equilibrium: N2(g)  +  3H2(g)    2NH3(g)  +  heat Which of the following changes would shift the equilibrium to the left? Please select all correct answers (there is more than one correct answer): increase the temperature removing some NH3 increasing the volume decreasing the volume decrease the temperature adding some NH3 removing some H2 adding some N2  

40 grams of ammonium chloride is dissolved in 100 grams of water at 10 degrees Celsius.  The solution is:

Please type in the proper name for the following molecule:  FeSO4

A sample of an element reveals that it has the following isotopes:  X-35, X-36, and X-37.  What is it’s average atomic mass?

When the equation: ___Al2(SO4)3  +  ___Ca(OH)2  –>  ___Al(OH)3  +  ___CaSO4 is correctly balanced with the smallest whole-number coefficients, the coefficient in front of Al(OH)3 will be:

Given the equation:  H2O  +  HF  H3O+  +  F-   , which of the following are Bronsted-Lowry acids?

Given the unbalanced reaction:  Al  +   H2SO4  –>   H2  +  Al2(SO4)3 The total number of moles of H2SO4 needed to react completely with 6.0 moles of Al is:

In a titration, the endpoint of a neutralization reaction was reached when 28.4 mL of an HCl solution was added 17.3 mL of a 0.250 M NaOH solution.  What was the molarity of the HCl solution?