chemistry - ASAP

posted by .

An unknown element reacts with bromine to give bromide, MBr3. If 2.809g of the unknown element gives 27.765grams of MBr3, what is the element? ( give the symbol )


I don't understand the M in the MBr3...can someoen please help me with this question ASAP

thanks a lot

  • chemistry - ASAP -

    M means some metal, such as Mg, Cr, Al. Note the metal is +3 valence.

    well, in the compound, it has 27.765grams, of which the metal is (27.765-2.809) grams, and the Br is 2.809 grams.

    Now, this you have 2.809grams Br, so you have 2.809/AtomicwtBr moles of Br.

    But in the formula, you have 1/3 this number of moles, or
    molesM=1/3*2.809/atomicwtBr

    Now the easy part.
    massM=molesM/atomicmassM

    solve for the atomicmassM
    and you can ID the Metal on the periodic table. Remember it is group +3, or +13, or a multivalent metal that can have a +3 valence.

  • chemistry - ASAP -

    "well, in the compound, it has 27.765grams, of which the metal is (27.765-2.809) grams, and the Br is 2.809 grams. " i don't understand this as you said br is 2.809 but the question says the unknown element is 2.809 grams?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry

    unknown element X combines with oxygen to form the compund XO2. If 44.0 grams of element X combines with 8.00 grams of oxygen, what is the atomic mass of element X?
  2. chemistry

    wen determining the formula for a compound its important to no the valance no of each element suppose element a has a valance no of 3 an element b has a valence no of 2 if the two elements combine then wen writing the formula for the …
  3. Chemistry

    Name and give the symbol for each of the following: a)the element in period 3 group 2 = Magnesium = Mg b)the halogen in period 4 = Bromine = Br c)the element in period 6 and group 11 = Gold = Au d)the akali metal in period 2 = Lithium …
  4. Physics HELP!

    You are at the controls of a particle accelerator, sending a beam of 3.90×10^7 m/s protons (mass m ) at a gas target of an unknown element. Your detector tells you that some protons bounce straight back after a collision with one …
  5. Chemistry

    An unknown element reacts with bromine to give bromide, MBr3. If 2.809g of the unknown element gives 27.765grams of MBr3, what is the element?
  6. Geometry

    If 3 us an element of A and 3 is not an element of B, then which of the following is NOT true 3 is an element of B complement 3 is an element of A union B 3 is an element of A intersect B
  7. chemistry

    an unknown element, X, reacts with chlorine to form an ionic compound XC12, if the X ion has 18 electrons, the element X is what?
  8. Chemimstry

    Consider this reaction involving an unknown element X. F2+2XBr = Br2+2XF When 5.200 g of XBr reacts, 2.896 g of Br2 is produced. Calculate the molar mass of XBr in g/mols?
  9. AP Chemistry

    Q - An electrochemical reaction occurs between an unknown element and zinc. The half-cell reaction for the zinc is: Zn(s) → Zn2+(aq) + 2e− The cell potential for the reaction is Eºcell = 1.83 V. Is the reaction spontaneous or …
  10. Chemistry

    Element X has a face-centered cubic unit cell structure. If the density of the element is measured to be 12.4 g/cm^3, what is the atomic radius of X?

More Similar Questions