- Below are allotropes of carbon.(Solved)
Below are allotropes of carbon.
(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.
(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.
(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.
(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) 
(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.
(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.
(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.
(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.
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.
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)
- Give equations to show the reactions that take place when;
(a) iron reacts with steam.
(b) Give one industrial use of the gas produced in the...(Solved)
Give equations to show the reactions that take place when;
(a) iron reacts with steam.
(b) Give one industrial use of the gas produced in the reactions in (a) above.
Date posted: September 12, 2019. Answers (1)
- Calculate the volume of nitrogen (I) oxide produced when 38.2g of ammonium nitrate is completely decomposed by heating
(at s.t.p). (N = 14, H = 1,...(Solved)
Calculate the volume of nitrogen (I) oxide produced when 38.2g of ammonium nitrate is completely decomposed by heating
(at s.t.p). (N = 14, H = 1, O = 16)
Date posted: September 12, 2019. Answers (1)
- Complete the table below.(Solved)
Complete the table below.
Date posted: September 12, 2019. Answers (1)
- Use the information in the table below to answer the questions that follow.(Solved)
Use the information in the table below to answer the questions that follow.
(a) Write the electron arrangement of:
(i) ion of S
(ii) atom of T
(b) Explain why the melting point of T is higher than that of U.
Date posted: September 12, 2019. Answers (1)