PRELIMINARY STAGE 2018
ROUND 2 - SPEED RACE
SPEED RACE (RIDDLES)
Sonrise SHS: 49 points
Opoku Ware School (OWASS): 46 points
Berekum SHS: 15 points
RIDDLE
I am an emitter of some sort.
I do not need electromagnetic radiation to function.
I work best with gases, but never mind — I have a chamber for vaporising solids and liquids too.
Who am I?
ANSWER: Mass spectrometer
EXPLANATION:
A mass spectrometer ionises a sample (an "emitter" of ions, via electron bombardment rather than electromagnetic radiation), then accelerates and deflects the ions through a magnetic field to separate them by mass-to-charge ratio; while it operates most simply with gaseous samples, an inlet/vaporisation chamber allows solid and liquid samples to be vaporised first.
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PRACTICE QUESTIONS
1. RIDDLE:
I am an analytical instrument.
I pass heat-carrying radiation through a sample.
Bonds in the sample absorb my radiation and vibrate.
I detect functional groups such as C=O and O–H.
My readout is plotted against wavenumber.
Breathalysers use my principle to detect ethanol.
Who am I?
ANSWER: INFRARED SPECTROMETER
EXPLANATION:
Infrared spectroscopy identifies bonds from the frequencies they absorb.
2. RIDDLE:
I am an instrument with a glass electrode.
I measure the hydrogen ion concentration of solutions.
My readings usually run from 0 to 14.
I must be calibrated with buffer solutions.
I am more precise than universal indicator.
My reading tells how acidic or alkaline a solution is.
Who am I?
ANSWER: PH METER
EXPLANATION:
A pH meter measures the potential of a glass electrode.
3. RIDDLE:
I am an evacuated glass vessel.
J.J. Thomson used me to discover the electron.
A high voltage drives a beam from my negative electrode.
Magnetic and electric fields bend my beam.
My beam makes a fluorescent screen glow.
Old television sets were built around me.
Who am I?
ANSWER: CATHODE RAY TUBE
EXPLANATION:
Cathode rays are streams of electrons.
4. RIDDLE:
I am an analytical instrument.
I turn samples into positive ions.
A magnetic field bends my ions by different amounts.
I sort ions by the ratio of their weight to their charge.
I find the relative abundances of isotopes.
Aston built an early version of me.
Who am I?
ANSWER: MASS SPECTROMETER
EXPLANATION:
A mass spectrometer separates ions by their mass-to-charge ratio.
5. RIDDLE:
I am a long glass tube with a tap.
My scale is marked in cubic centimetres.
I deliver accurately measured volumes of liquid.
I am used in titrations.
I am read at the bottom of the meniscus.
I am clamped vertically above a conical flask.
Who am I?
ANSWER: BURETTE
EXPLANATION:
A burette measures the volume of titrant added.
6. RIDDLE:
I split light into its colours.
I use a prism or a diffraction grating.
I show the line spectra of elements.
Helium was first found on the Sun with me.
Bunsen and Kirchhoff discovered caesium with me.
I identify metals in flame tests precisely.
Who am I?
ANSWER: SPECTROSCOPE
EXPLANATION:
Each element has its own pattern of spectral lines.