A group of learners prepare a 0,25 mol∙dm-3 solution of sodium carbonate by dissolvinga 14,2 g sample of hydrated sodium carbonate (Na2CO3∙xH2O) in 200 cm3 of water. 7.1 Explain the meaning of the term hydrated. (1) 7.2 Write down a BALANCED CHEMICAL EQUATION to show how sodium carbonate dissociates in water. (2) 7.3 Learners then … Read more
Study the diagram below showing structures of two different substances (A and B) andanswer the questions that follow. 6.1 Choose the substance (A or B) that describes the following: 6.1.1 Metallic structure (1) 6.1.2 Structure of magnesium chloride (1) 6.2 Explain how the type of bond in substance A forms. (2) 6.3 Name the type … Read more
Study the physical and chemical processes below and answer the questions thatfollow. X: H2O(s) → H2O(g)Y: CaCO3(s) ∆ → CaO(s) + CO2(g)Z: Iron + Oxygen → Iron(III) oxide 5.1 Define the term physical change. (2) 5.2 Write down the LETTER of the process that represents the following: 5.2.1 Physical change (1) 5.2.2 Decomposition reaction (1) … Read more
Study the table below and answer the questions that follow. 4.1 Define the term atomic number. (2) 4.2 Write down the: 4.2.1 Chemical symbol of element Q using the notation (2) 4.2.2 Element (P, Q or R) that is an alkali metal (1) 4.2.3 Chemical symbol of R (2) 4.3 Element P reacts with oxygen … Read more
The vapour pressure versus temperature graph below was obtained for four unknownliquids (A, B, C and D). Atmospheric pressure is measured as 101,3 kPa. 3.1 Define the term boiling point. (2) Use the information given in the graph to answer the questions that follow. 3.2 Write down the: 3.2.1 Boiling point of liquid B (1) … Read more
The diagram below shows three different substances, P, Q and R. 2.1 Define the term element. (2) Use the diagram and the key provided to answer the questions that follow. 2.2 Write down a LETTER that represents the following: 2.2.1 Pure substance (1) 2.2.2 Homogeneous mixture (1) 2.2.3 Heterogeneous mixture (1) 2.3 Indicate whether the … 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 the letter(A–D) next to the question numbers (1.1 to 1.10) in the ANSWER BOOK, e.g. 1. 11 D. 1.1 Which ONE of the following substances is NOT a pure substance? A IronB … 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 the letter(A–D) next to the question numbers (1.1 to 1.10) in the ANSWER BOOK, e.g. 1.11 D. 1.1 An object is positively charged if it has more … A electrons than protons.B … Read more