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…
Nomex is a synthetic fibre used in fire-resistant clothing. It is a polyamide formed from the two monomers shown. Draw one repeating unit of Nomex.
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.
The concentration of protein in egg white was determined by a dye-binding method. The absorbance at 595 nm of protein solutions of known concentration was used to draw a calibration line, with the equation shown. Calculate, using the linear equation, the…
Maltose is a disaccharide made of two glucose units. State the type of reaction in which a disaccharide forms from two monosaccharide molecules.
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.
Some bacteria can be used in microbial fuel cells to oxidize aqueous lactate ions, CH3CH(OH)COO−(aq), to carbon dioxide gas. Oxygen gas is reduced at the other electrode. The cell operates in acidic conditions. Deduce the half-equations for the…
A hydrogen fuel cell and a rechargeable lithium-ion cell can both be used to supply electricity again and again. Describe, for each type of cell, what must be done so that it can be used again after the cell can no longer supply electricity.
Benzocaine is a local anaesthetic. It is made by reacting the carboxylic acid X with ethanol. (i) Discuss two ways in which the melting point of a crystallized sample of benzocaine can show that it still contains X. (ii) Deduce the range of wavenumbers in the…
Menthol is a secondary alcohol used in cough lozenges. A chemist heated menthol with an oxidizing agent and isolated the product, which is either unreacted menthol or its oxidation product menthone. The structures of the two compounds and the IR spectrum of…
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.
Ibuprofen and glyceryl trinitrate (GTN) are two drugs with the structures shown. Deduce, giving a reason, whether the 1H NMR spectrum of ibuprofen or of GTN has signals with chemical shifts in the 6.9–9.0 ppm region. Use section 21 of the data booklet.
Salbutamol, used to treat asthma, has a relative molecular mass Mr = 239. Its mass spectrum has a peak at m/z = 221. Suggest a neutral fragment whose loss could account for this peak. Use section 22 of the data booklet.