Learners made a mini volcano in a science laboratory by adding sodium bicarbonate toethanoic acid. They added 100 mℓ of a 0,2 mol. dm-3 ethanoic acid solution to 10 g of NaHCO3 to start the reaction of the volcano.The balanced equation for this reaction is: CH3COOH(aq) + NaHCO3(s) → CH3COONa(aq) + H2O(l) + CO2(g) 6.1 … Read more
5.1 Define the term concentration. (2) 5.2 Eight (8) grams of Na2S2O3 is dissolved in water to prepare 500 cm3 ofsolution. Calculate the concentration of the Na2S2O3 solution. (3) 5.3 A 10 g sample of a compound contains 2,66 g of potassium, 3,54 g ofchromium and 3,81 g of oxygen. 5.3.1 Define the term empirical … Read more
4.1 Charles’ Law describes the relationship between the volume and temperatureof an enclosed mass of gas at constant pressure. The volumes of a gas atdifferent temperatures at constant pressure are given in the table below. 4.1.1 Explain Charles’ Law in terms of the kinetic molecular theoryof gases. (2) 4.1.2 Draw a graph of volume versus … Read more
Learners conduct an experiment to investigate the effects of intermolecular forces onboiling points. They use 20 mℓ of each of the following compounds in theirinvestigation: water, sunflower oil, nail polish remover, glycerine and methylated spirits.The results are shown in the table below: 3.1 Define the term boiling point. (2) 3.2 Formulate an investigative question for … Read more
Electronegativity of atoms may be used to explain the polarity of bonds. 2.1 Define the term electronegativity. (2) 2.2 Draw the Lewis diagram of an oxygen difluoride molecule. (2) 2.3 Calculate the electronegativity difference between O and F in oxygendifluoride and predict the polarity of the bond. (2) 2.4 A polar bond does not always … Read more
A heavy object is lifted using two ropes and two pulleys, as shown in the diagram below. The two pulleys are a distance x apart. The force FA, in rope A, is 730 N and the force FB, in rope B, is 1 440 N. Rope A makes an angle of 70° with the horizontal … Read more
MULTIPLE-CHOICE QUESTIONS Four options are provided as possible answers to the following questions.Each question has only ONE correct answer. Choose the answer and write onlythe letter (A–D) next to the question number (1.1–1.10) in the ANSWER BOOK,for example 1.11 E. 1.1 The type of bond formed between a H+ ion and H2O is called a/an … Read more
Four options are provided as possible answers to the following questions. Each question has only ONE correct answer. Choose the answer and write only the letter (A–D) next to the question number (1.1–1.10) in the ANSWER BOOK, for example 1.11 E. 1.1 Four forces act on a point, as indicated in the diagram. The magnitudes … Read more
O is the centre of the bigger circle. O lies on the circumference of the smaller circle. OWVU are points on the circumference of the smaller circle. TSVU are points on the circumference of the bigger circle. 10.1 Name FOUR other angles each equal to 𝑥 with reasons. (8) 10.2 Determine the size of Ŵ2 … Read more