Zadania wzorowane na pytaniach z tego arkusza: te same umiejętności, format i punktacja, inne dane i kontekst. Treści arkusza IB nie publikujemy.
Dodaj cały arkusz do zestawu(i) Identify the dependent variable plotted on the graph. (ii) Calculate the decrease in the concentration of vitamin C, in μg cm−3, caused by the heat treatment. (iii) Calculate the average rate of decrease of the vitamin C concentration in…
UV-C irradiation is an alternative to heat treatment that causes less loss of nutrients. The absorption spectrum of a solution of vitamin C is shown. (i) Deduce the type of electromagnetic radiation absorbed by vitamin C. Use section 5 of the data booklet.…
The concentration of vitamin C and the pH of juice from five different fruits were measured. Deduce, with a reason, whether the data show a correlation between the concentration of vitamin C and pH.
The concentration of vitamin C in juice can be measured by a redox titration. A sample of acidified juice containing excess iodide ions and starch solution is titrated with potassium iodate solution. Iodate ions react with iodide ions to produce iodine…
Lithium hydride, LiH, forms a crystalline ionic lattice made of Li+ and H− ions. Deduce, giving a reason, whether lithium hydride could be classified as a Brønsted–Lowry acid or as a Brønsted–Lowry base.
Graphite foil is made of many layers of carbon atoms stacked on top of each other. It is used to spread heat away from the processor of a mobile phone because it conducts heat well parallel to the layers but poorly perpendicular to them. Suggest why graphite…
A student electrolysed aqueous silver nitrate between two silver electrodes, as shown. Each electrode was washed, dried and weighed before and after the electrolysis. Suggest why the mass gained by the cathode is a less accurate measure of the amount of silver…
Proteins are polymers of amino acids. State the type of bonding that joins the amino acids together along a polypeptide chain.
A biochemist wants to find out which of the amino acids glycine, serine and leucine are present in a short peptide. Outline how paper chromatography can be used to do this.
Natural gas is a fossil fuel used for heating homes. State the molecular formula of the main component of natural gas.
Outline one advantage and one disadvantage, apart from cost, of using natural gas rather than coal as the fuel in a power station.
Benzocaine is a local anaesthetic. It is made by reacting the carboxylic acid X with ethanol. Discuss two ways in which the melting point of a crystallized sample of benzocaine can show that it still contains X.
Calcium carbonate is an active ingredient in some antacid tablets. Write an equation, including state symbols, for the reaction of calcium carbonate with the hydrochloric acid in the stomach.