Get premium membership and access questions with answers, video lessons as well as revision papers.
- The sketch of the graph below shows a reaction between magnesium ribbon and dilute hydrochloric acid.(Solved)
The sketch of the graph below shows a reaction between magnesium ribbon and dilute hydrochloric acid.
![Q2691320191105.png](/questions/uploads/Q2691320191105.png)
(a) On the graph indicate the curve for 0.05M HCl
(b) Other than change in concentration, name two other factors that can affect the rate of reaction above.
Date posted: September 13, 2019. Answers (1)
- Study the flow chart below carefully.(Solved)
Study the flow chart below carefully.
![Q2591320191055.png](/questions/uploads/Q2591320191055.png)
(a) Identify the cat-ion in the colourless solution N.
(b) Write ionic equations for the reactions in Step I.
Date posted: September 13, 2019. Answers (1)
- Study the energy level diagram below and use it to answer the questions that follow.(Solved)
Study the energy level diagram below and use it to answer the questions that follow.
![Q2391320191034.png](/questions/uploads/Q2391320191034.png)
(a) Identify the heat change ![Q2391320191037.png](/questions/uploads/Q2391320191037.png)
(b) Given that the heat change for ![Q2391320191038.png](/questions/uploads/Q2391320191038.png)
Calculate the heat change for the reaction ![Q2391320191041.png](/questions/uploads/Q2391320191041.png)
Date posted: September 13, 2019. Answers (1)
- The following diagram shows how chlorine gas can be prepared in the laboratory.(Solved)
The following diagram shows how chlorine gas can be prepared in the laboratory.
![Q1991320191020.png](/questions/uploads/Q1991320191020.png)
Complete the diagram
Date posted: September 13, 2019. Answers (1)
- Below are allotropes of carbon.(Solved)
Below are allotropes of carbon.
![Q1891320191004.png](/questions/uploads/Q1891320191004.png)
(i) Identify allotrope A and B
(ii) With a reason, identify the allotrope that can be used in the making of pencil.
Date posted: September 13, 2019. Answers (1)
- A compound of carbon hydrogen and oxygen contains 57.15% carbon, 4.76% hydrogen and rest oxygen. If its relative molecular mass is 126, find its molecular...(Solved)
A compound of carbon hydrogen and oxygen contains 57.15% carbon, 4.76% hydrogen and rest oxygen. If its relative molecular mass is 126, find its molecular formula. (C = 12, H = 1, O = 16)
Date posted: September 13, 2019. Answers (1)
- The following table shows the effect of heat on three metal nitrates P, Q and R.(Solved)
The following table shows the effect of heat on three metal nitrates P, Q and R.
![Q139132019933.png](/questions/uploads/Q139132019933.png)
(a) Arrange the metals P,Q and R in order of decreasing reactivity.
(b) Name a metal that is likely to be
(i) R
(ii) Q
Date posted: September 13, 2019. Answers (1)
- Study the heating curve below and answer the questions that follow.(Solved)
Study the heating curve below and answer the questions that follow.
![Q119132019925.png](/questions/uploads/Q119132019925.png)
(i) Identify the process taking place between B and C
(ii) Is the process you have named above endothermic or exothermic? Explain
Date posted: September 13, 2019. Answers (1)
- Substance A reacted with both an acid and a base as shown below.(Solved)
Substance A reacted with both an acid and a base as shown below.
![Q109132019917.png](/questions/uploads/Q109132019917.png)
(i) State the nature of A
(ii) Name any two oxides of A
Date posted: September 13, 2019. Answers (1)
- Give the IUPAC name of the following compound.(Solved)
Give the IUPAC name of the following compound.
(a) ![Q89132019906.png](/questions/uploads/Q89132019906.png)
(b) Describe a chemical test that can be used to distinguish between compound (i) and (iii)
Date posted: September 13, 2019. Answers (1)
- A 2.0g of limestone was allowed to react with 200cm3 of 0.2MHCl acid. The excess acid required 49.6cm3 of 0.1M NaOH solution. Calculate the percentage...(Solved)
A 2.0g of limestone was allowed to react with 200cm3 of 0.2MHCl acid. The excess acid required 49.6cm3 of 0.1M NaOH solution. Calculate the percentage of calcium carbonate in the limestone. (Ca = 40, C = 12, O = 16)
Date posted: September 13, 2019. Answers (1)
- The table below represents elements P, Q, R and S. Study it answer the questions that follow. (The letters are not the actual symbols of...(Solved)
The table below represents elements P, Q, R and S. Study it answer the questions that follow. (The letters are not the actual symbols of the elements.
![Q59122019847.png](/questions/uploads/Q59122019847.png)
(a) Explain why the atomic radius of element P is greater than that of element R.
(b) Explain why the atomic radius of element R is less than its ionic radius.
(c) Using dots and crosses (X) show bonding in the compound formed between elements Q and R.
Date posted: September 13, 2019. Answers (1)
- The diagram below was used to prepare gas X.(Solved)
The diagram below was used to prepare gas X.
![Q9132019837.png](/questions/uploads/Q9132019837.png)
(a) Identify gas x.
(b) Write an equation for the reaction that took place.
(c) Identify the method of gas collection above.
Date posted: September 13, 2019. Answers (1)
- A volume of 80cm3 of nitrogen gas diffused through an office in 40 seconds. How long will 170cm3 of carbon (IV) oxide take to diffuse...(Solved)
A volume of 80cm3 of nitrogen gas diffused through an office in 40 seconds. How long will 170cm3 of carbon (IV) oxide take to diffuse through the same office? (N = 14, C = 12, O = 16)
Date posted: September 13, 2019. Answers (1)
- The figure below shows part of a Bunsen burner. Study it and answer the questions that follow.(Solved)
The figure below shows part of a Bunsen burner. Study it and answer the questions that follow.
![Q19132019812.png](/questions/uploads/Q19132019812.png)
(a) Name labelled parts B and D.
(b) State the function of the part labelled B.
Date posted: September 13, 2019. Answers (1)
- The following results were obtained during an experiment to determine the solubility of potassium nitrate in water at 300C.
Mass of dish = 15.86g, mass of...(Solved)
The following results were obtained during an experiment to determine the solubility of potassium nitrate in water at 300C.
Mass of dish = 15.86g, mass of dish + saturated solution at 300C= 26.86g, mass of dish + solid KNO3 after evaporation to dryness = 16.7g. Calculate the mass of saturated solution containing 60.0g of water at 300C.
Date posted: September 12, 2019. Answers (1)
- Give the name of the following organic compounds.(Solved)
Give the name of the following organic compounds.
![Q309122019104.png](/questions/uploads/Q309122019104.png)
Date posted: September 12, 2019. Answers (1)
- Below is a scheme of some reactions starting with but-z-yne. Study it and answer the questions that follow.(Solved)
Below is a scheme of some reactions starting with but-z-yne.
![Q3091220191259.png](/questions/uploads/Q3091220191259.png)
Study it and answer the questions that follow.
(a) Name Y, X and T
Date posted: September 12, 2019. Answers (1)
- What is an amphoteric oxide?(Solved)
What is an amphoteric oxide?
Date posted: September 12, 2019. Answers (1)
- Explain why chlorine is a gas while iodine is a solid at room temperature.(Solved)
Explain why chlorine is a gas while iodine is a solid at room temperature.
Date posted: September 12, 2019. Answers (1)