Grade 11 Physical Science 2017 Paper 2

Gold and iron are two of many minerals mined in South Africa. Iron is mined inopen-cast mines, while gold is usually found in deep-shaft (underground) mines.During the process of refining, the following chemical reactions take place to extractthe metal from the ore: Gold is dissolved in a solution containing cyanide ions (CN–) to extract it … Read more

The reaction between dichromate ions (Cr2O7-2) and iron(II) ions (Fe2+) in an acidic medium is given below. 9.1 Determine the oxidation number of CHROMIUM in Cr2O7-2(aq).(2) 9.2 Define reduction in terms of electron transfer.(2) 9.3 Write down the FORMULA of the substance that undergoes oxidation. Explainthe answer in terms of oxidation numbers.(2) 9.4 Write down … Read more

8.1 Two reactions of sulphuric acid are shown in the diagram below. 8.1.1 Define a Lowry-Brønsted base.(2) 8.1.2 Write down a balanced equation for Reaction 1.(3) 8.1.3 Write down the NAME of the salt represented by X.(2) 8.1.4 Write down the FORMULA of ampholyte A.(2) 8.1.5 Write down the formulae of the TWO conjugate acid-base … Read more

The equation for the combustion of butane gas is given below. 7.1 Define the term activation energy.(2) 7.2 Is the combustion reaction of butane exothermic or endothermic? Give areason for the answer.(2) 7.3 Draw a sketch graph of potential energy versus course of reaction for thereaction above. Clearly indicate the following on the graph: Activation … Read more

6.1 The decomposition of hydrogen peroxide in the presence of a catalyst at standard pressure and room temperature is given by the unbalanced chemical equation below. The oxygen gas is collected and the volume is recorded over a period of time.The reaction is completed at time t. The results are plotted on a graph of … Read more

Weather balloons are sent into space to gather data. The balloons usually burst at apressure of 27 640 Pa and a volume of 36,3 m3. The data collector then falls back to Earth. The gas in a certain weather balloon has an initial volume of 12,6 m3 and pressure of105 000 Pa at a temperature … Read more

In an experiment to investigate the relationship between pressure and temperature ofan enclosed gas, 48 g of oxygen gas was sealed in a container. The results obtainedare recorded in the table below. 4.1 Draw a graph of pressure versus temperature on the attached ANSWERSHEET. Extrapolate the graph so that it intersects the y-axis. (4) 4.2 … Read more

Consider the list of six substances with their formulae and boiling points in the tablebelow. 3.1 Explain why ethanol is soluble in water. Refer to the relative strength of theintermolecular forces in ethanol and water. (3) 3.2 Explain why the boiling point of iodine is higher than that of bromine. Refer tothe intermolecular forces present … Read more