First of all, you need to know how many g of Mg actually reacted in the first reaction. You can determine this by determining the limiting reactant.

The reaction is
Mg + F2 -> MgF2

16.2 g of Mg is 16.2/24.32 = 0.666 moles
25.3 g of F2 is 25.3/38.0 = 0.666 moles

So equal numbers of moles are consumed. There is no limiting reactant in this case. I should have realized this wehen the problems stated that the Mg reacts exactly with 25.3 g.

10.5 g is 64.8% of 16.2. When you have excess fluorine, you will get 64.8% as much product as you did in the first (complete) reaction. That would be 0.648 x 0.666 = 0.432 moles of MgF2. Each mole of MgF2 has a mass of 62.32 g. That means you make 26.9 g of MgF2.

I quicker way to get the answer is:
MgF2 formed = (10.5/16.2)(16.2 + 25.3), which is 64.8% of the total mass of reactants in the first (complete) reaction.

  1. 👍
  2. 👎
  3. 👁

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    A 0.879 g sample of a CaCl2 ∙ 2 H2O / K2C2O4 ∙ H2O solid salt mixture is dissolved in 150 mL of deionized water. A precipitate forms which is then filtered and dried. The mass of this precipitate is 0.284 g. The limiting

  2. chemistry

    Consider the following reaction: 2H2 (g) + O2 (g)  2H2O (l) ΔH = -572 kJ a. How much heat is evolved for the production of 1.00 mol H2O (l)? b. How much heat is evolved when 4.03 g hydrogen is reacted with excess oxygen? c.


    Please explain the answer. Which statement about this reaction is correct? 2Fe(s)+3CO2(g)--->Fe2O3(s)+3CO(g) delta H = 26.6 kJ A. 26.6 kJ of energy are released for every mole of Fe reacted B. 26.6 kJ of energy are absorbed for

  4. Chemistry

    When 0.40 g of impure zinc reacted with an excess of hydrochloric acid, 127 mL of hydrogen was collected over water at 10 degress C The external pressure was 737.7 Torr. a) What volume would the dry hydrogen occupy at 1.00 atm and

  1. Chemistry

    The overall reaction in a commercial heat pack can be represented as shown below. 4 Fe(s) + 3 O2(g) 2 Fe2O3(s) ΔH = -1652 kJ How much heat is released when 4.00 mol iron is reacted with excess O2? How much heat is released when

  2. Chemistry --really need help!

    I am really struggling with these problems!! A reaction mixture that consisted of 0.20 mol N2 and 0.20 mol H2 was introduced into a 25.0 L reactor and heated. At equilibrium, 5.0% of the nitrogen gas has reacted. What is the value

  3. Chemistry complex ions

    Al and Zn both form hydroxides when reacted with an NH3 sloution and NaOH solution The hydroxides are both amphoteric When you add excess NH3 the Zn ppt dissolves, but Aluminium stays When you add excess NaOH both ppts dissolve


    How many stereoisomers are there for 1,2-dichlorocyclopentane?: a) 1 b) 2 c) 3 d) 4 answer: "B" (2)??? or: "D" (4)??? How many stereoisomers are possible for: cortisone acetate?: a) 32 b) 64 c) 128 d) 256 answer: "B" (64)??? How


    Hydrogen cyanide, HCN, can be made by a two-step process. First, ammonia is reacted with O2 to give nitric oxide, NO. 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) Then nitric oxide is reacted with methane, CH4. 2 NO(g) + 2 CH4(g) →

  2. Analytical Chemistry

    A 10.0 mL sample of whiskey was diluted to 500.0 mL. A 4.00 mL aliquot of the diluted sample was removed and the ethanol, C2H5OH, was distilled into 50.00 mL of 0.02150 M K2Cr2O7 and oxidized to acetic acid. The excess Cr2O72–

  3. chemistry

    400 cm3 of 0.5mol/dm3 hydrochloric acid was reacted with 5g of magnesium oxide. Calculate the mass of reacted oxide? Show the steps and thq..

  4. Chemistry

    4.80 dm^3 of chlorine gas was reacted with NaOH solution. a) how many moles of Cl2 reacted b) what mass of NaOCl was formed? c) if the concentration of the NaOH was 2.00 mol/dm^3. What volume of sodium hydroxide solution was

You can view more similar questions or ask a new question.