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
- i know this question was posted earlier but i did not understand something and bob did not reply to my question ( no prob , i understand you guys are busy but i really need help with this question, its worth a lot and im freaking out for the test tomm )
The M stands for the unknown element; it binds to the Bromine. Bromine has a -1 charge, and there are three, it is highly likely that the element is Aluminum or Boron.
27.765 g MBr3-2.809 g M=24.956 g 3Br-
24.956 g Br* (1 mol Br/239.7 g)=
.104 mol Br
This is the same number as that of M, so there are .104 mol M.
2.809 g M/.104 mol M=26.98 g/mol M.
This is the molar mass of aluminum.
Well, well, well, it seems like you're in a bit of a pickle. Don't worry, I'm here to clown around and help you out! Let's break it down, shall we?
So, we have an unknown element that reacts with bromine to form MBr3. The "M" in MBr3 simply represents the unknown element, kind of like a secret code name. Now, the problem tells us that 2.809 grams of the unknown element gives us 27.765 grams of MBr3.
To find out what the unknown element is, we need to figure out its atomic mass. We can do this by comparing the mass of the unknown element to the mass of MBr3.
First, let's find the molar mass of MBr3. The molar mass of bromine (Br) is 79.904 grams/mol, and since we have three of them in MBr3, the molar mass of MBr3 is 3 x 79.904 = 239.712 grams/mol.
Now, we can set up a proportion using the masses of the unknown element and MBr3:
(mass of unknown element)/(molar mass of unknown element) = (mass of MBr3)/(molar mass of MBr3)
Plugging in the given values:
2.809g/x = 27.765g/239.712g/mol
Now, cross multiply and solve for x:
2.809g * 239.712g/mol = 27.765g * x
672.612408g/mol = 27.765g * x
Divide both sides by 27.765g to isolate x:
672.612408g/mol / 27.765g = x
x ≈ 24.18 g/mol
And there you have it, the approximate molar mass of the unknown element is 24.18 g/mol. Now, we can use the periodic table to find the element that has a molar mass close to 24.18 g/mol. Can you take it from here?
The "M" in MBr3 represents the unknown element. In chemical equations, "M" is often used as a placeholder for a generic or unknown element.
To determine the identity of the unknown element, we can use the given information about the mass of the unknown element and the mass of MBr3 produced.
1. Convert the mass of the unknown element (2.809g) to moles. To do this, divide the mass by the molar mass of the unknown element.
You would need to refer to the periodic table to determine the molar mass of the unknown element.
2. Convert the mass of MBr3 (27.765g) to moles. To do this, divide the mass by the molar mass of MBr3.
First, find the molar mass of MBr3. The molar mass of bromine (Br) is approximately 79.90 g/mol. Since there are three bromine atoms in MBr3, the molar mass of MBr3 is 3 times the molar mass of bromine.
3. Compare the mole ratios of the unknown element and MBr3. The chemical formula MBr3 implies that one mole of the unknown element reacts with three moles of bromine to produce one mole of MBr3.
Calculate the mole ratios by dividing the number of moles of each substance by the smallest number of moles.
4. Based on the mole ratio, determine the periodic table element that corresponds to the unknown element.
For example, if the mole ratio is 1:3 (1 mole of M reacts with 3 moles of Br), then M represents the element from Group 13 of the periodic table, which includes elements such as boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl).
By following these steps and considering the given information, you should be able to determine the symbol of the unknown element.
Don't worry, I'm here to help! The "M" in MBr3 is just a placeholder for the unknown element. To find out the symbol of the unknown element, we need to use the given information and perform some calculations.
First, we need to determine the number of moles of MBr3 produced from the given mass. We can do this by dividing the mass of MBr3 (27.765 grams) by its molar mass.
The molar mass of MBr3 can be calculated by adding up the molar masses of one mole of the unknown element (M) and three moles of bromine (Br).
Using the molar masses from the periodic table, we find that the molar mass of bromine (Br) is approximately 79.9 g/mol.
Now, let's use the given mass of MBr3 (27.765 grams) and its molar mass to calculate the number of moles:
Number of moles of MBr3 = mass / molar mass
= 27.765 g / (Molar mass of M + 3 × Molar mass of Br)
Since we are assuming 2.809 grams of the unknown element reacts to form 27.765 grams of MBr3, we can set up the following equation:
2.809 g / Molar mass of M = 27.765 g / (Molar mass of M + 3 × 79.9 g/mol)
Now, let's solve this equation for the molar mass of M, which will help us determine the symbol of the unknown element.
Cross-multiplying the equation, we get:
2.809 g × (Molar mass of M + 3 × 79.9 g/mol) = 27.765 g × Molar mass of M
Expanding and rearranging the equation:
2.809 (Molar mass of M) + 3 × 2.809 × 79.9 g/mol = 27.765 × (Molar mass of M)
2.809 (Molar mass of M) - 27.765 (Molar mass of M) = - 3 × 2.809 × 79.9 g/mol
Simplifying:
- 25.956 (Molar mass of M) = - 3 × 2.809 × 79.9 g/mol
Finally, solving for the molar mass of M:
Molar mass of M = (- 3 × 2.809 × 79.9 g/mol) / (- 25.956)
= (251.9586 g/mol) / 25.956
≈ 9.71 g/mol
Now, we have the molar mass of the unknown element (M) as approximately 9.71 g/mol. We can consult the periodic table to find the element with a molar mass close to 9.71 g/mol, and its symbol is Hg, which corresponds to mercury.
Therefore, the unknown element M is mercury, and its symbol is Hg.