1. Compound x contains only boron and hydrogen. The percentage by mass of boron in X is 81.2%. In the mass spectrum of X the largest value of m/z occurs at 54.
a. Use the percentage by mass data to calculate the empirical formula of X.I did this and got B2H5. Is this correct? I can type up my working out, if needed.
b. Deduce the molecular formula of X.I know how to do this, but for some reason I can't figure out an answer because regardless of how many times I try, the Mr of the compound. doesn't add up to 54.
2. In a mass spectrometer, a chlorine molecule forms a molecular ion Cl2+. State the no. of lines present in the mass spectrum of chlorine that are due to the molecular ions of chlorine, and deduce and explain their relative heights.
a. Number of linesThis would be three wouldn't it?
b. Relative heightsI'm not too sure what this would be. I know 35Cl and 37Cl are found in the ratio 3:1, so presumably the 35Cl-35Cl molecule would be three times higher than the 37Cl-37Cl molecule, wouldn't it? How high would the 35Cl-37Cl molecule be?
3. Hydrogen (Mr=2) was reacted with an excess of chlorine gas. When the resulting gaseous mixture was analysed using a mass spectrometer, five lines representing molecular ions were seen in the mass spectrum.
(The mass spectrum is shown below)
a.
Give the formula of the species represented by the line in the spectrum above, indicating the mass number of each of the atoms present.The m/z is 36 so it would be HCl? Cl would have an Ar of 35 and H an Ar of 1.
b.
Draw a line of the spectrum above to represent another molecular ion species presentCould I just draw a line at m/z 37 which would be H2Cl. Is this right?
c.
The complete mass spectrum of the mixture contains three lines with m/z values outside the range shown in the mass spectrum above (goes up to 40). State the values at which these lines appear.I don't understand how to find out what the values are.
Any help at all would be appreciated!