The table shows the concentrations, in arbitrary units, of four substances. These substances are present in each of two animal cells, K and L, whose cell membranes are in contact.…

A sample of an acid, H2X, weighing 4.5g was dissolved in water. This solution was neutralised by 50.0cm3 of aqueous sodium hydroxide containing 2mol/dm3. What is the relative molecular mass,…

A sample of rock contains 235U and 207Pb in the proportion one part 235U to seven parts 207Pb. It is known that 235U decays to 207Pb with a half life…

Evaluate: Answer: 17) A We know the general quadratic formula (a – b)² = a² – 2ab + b² So we have, (√5 – √2)² = (√5)² – [2 (√5)…

A pulse of frequency 100kHz is emitted from an ultrasound scanner, and is reflected from a fetus 10cm below the transmitter placed on the mother’s abdomen. The speed of sound…

Rearrange the following equation to give x in terms of y. Answer: 13) A y = ⎡x² + 2ax⎤½       ⎣     b       ⎦ y²…

Which row of the table shows what occurs in the eye when you watch a bird flying away from you? Answer: 12) B Don’t worry if you do not know…