Four metals, labelled R, T, X and Z, have the following characteristics: R fizzes when added to dilute hydrochloric acid. T is precipitated when R reacts with an aqueous solution…

Several processes can change the proportion of gases in the atmosphere by adding or removing carbon dioxide or oxygen. Which row is correct? Answer: 13) D This is fairly simple.…

Triangle PQR is equilateral with sides of length 10 cm. P, Q, and R are points on the circumference of a circle with centre O. Which one of the following…

A ‘gold medal’ used in events such as the Olympic Games is made from a silver–nickel alloy with a coating of a gold–silver alloy.The mass of the medal is 256…

The reaction between hydrogen and nitrogen in the presence of an iron catalyst is known as the Haber process. It is a reversible reaction. The energy profile for this reaction…

Some rabbits have a genetic condition. The dominant allele codes for this condition. A homozygous dominant rabbit mated with a rabbit that did not have the condition. They had three…

In a sale, the normal price of a camera is reduced by 20%. The sale price of the camera is £180. Which expression gives the normal price of the camera?…

An electric fan heater contains a heating element and a motor that drives the fan. The circuitdiagram is shown.At first, the switch is open and the current in the motor…