6.1 Study the balanced chemical equation of the reaction between sodium carbonate (Na2CO3) and hydrochloric acid (HCâ„“) and answer the questions that follow. Na2CO3 + 2HCâ„“ → 2NaCâ„“ + CO2 + H2O Identify the type of reaction above. Choose between REDOX and GAS FORMING. (1) 6.2 In a reaction, 10,6 g of sodium carbonate reacts … Read more
Hydrogen peroxide decomposes at room temperature according to the following balanced chemical equation: 2H2O2(aq) → O2(g) + 2H2O(â„“) 5.1 What does the (aq) represent in the equation above? (1) 5.2 Identify the type of reaction above. Choose between PRECIPITATION and REDOX. Give a reason for the answer. (2) 5.3 Is the reaction an example of … Read more
4.1 A certain element, X, has two isotopes in nature. One isotope has an atomic mass of 106,9 amu. The percentage appearance of this isotope is 50%.The atomic mass of the other isotope is 109,1. 4.1.1 Define the term isotope. (2) 4.1.2 Calculate the relative atomic mass of element X. (5) 4.1.3 Identify element X … Read more
Consider the graph of the first ionisation energy and answer the questions that follow. 3.1 Define the term ionisation energy. (2) 3.2 State the general trend in ionisation energy from left to right across a periodon the periodic table. (2) 3.3 There is a drop in ionisation energy from beryllium to boron. 3.3.1 Write down … Read more
Consider the following substances: C90; NaCâ„“; CO2; Fe; H2O 2.1 Write down a substance from the list above that is the following: 2.1.1 A molecular structure (1) 2.1.2 A metallic structure (1) 2.1.3 A covalent network structure (1) 2.1.4 An ionic network structure (1) 2.2 Draw the Lewis dot diagram for the CO2 molecule. (2) … Read more
Various options are provided as possible answers to the following questions. Eachquestion has only ONE correct answer. Choose the answer and write only theletter (A–D) next to the question number (1.1–1.10) in the ANSWER BOOK, forexample 1.11 E. 1.1 Air can be classified as a/an …A element.B compound.C homogenous mixture. D heterogeneous mixture. (2) 1.2 … Read more