A sample of butane, C4H10 is treated with deuterium, D (an isotope of hydrogen) and some of the hydrogen atoms are replaced by deuterium atoms. Analysis shows that the substituted…

When a 1kg mass is dropped from the top of a building 20m high it hits the Earth with a speed of 20m/s. What would be its speed if the…

In the shape shown below, A, B and C are the vertices of an equilateral triangle, side length xcm. The arc AC forms a semicircle. Which of the following alternatives…

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…