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…

Hot, concentrated aqueous sodium hydroxide and chlorine react as shown in the equation:6NaOH + 3Cl2 → 5NaCl + NaClO3 + 3H2OWhich of the following statements is/are correct?1 Chlorine has oxidation…

Scientists are using human stem cells to develop treatments for a wide variety of healthconditions.Two types of stem cell that are available for this work are: stem cells collected from…