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a) Black copper II oxide changes to brown copper metal
b) i) Y changes white anhydrous Copper II Sulphate to a blue colour/OR changes blue cobalt chloride paper
to pink colour
ii) x is nitrogen gas
sharon kalunda answered the question on March 27, 2019 at 14:02
- Given element W has atomic number 14 and consists of isotopes as shown below.
Isotope ...(Solved)
Given element W has atomic number 14 and consists of isotopes as shown below.
Isotope A B C
Isotope mass 28 29 30
Percentage abundance 92.2 4.7 3.1
Determine the relative atomic mass of W
Date posted: March 27, 2019. Answers (1)
- The set up was used to prepare dry hydrogen gas. Study it and answer the questions that follow.(Solved)
The set up was used to prepare dry hydrogen gas. Study it and answer the questions that follow.
i) Is set-up used to prepare the gas correct? Give reason.
(ii) What would be liquid Y?
(iii) Give two physical properties of hydrogen gas
Date posted: March 27, 2019. Answers (1)
- Relative molecular mass of methane and water are almost similar, however the boiling of water is 1000C while that of methane is -1610C. Explain.(Solved)
Relative molecular mass of methane and water are almost similar, however the boiling of water is 1000C while that of methane is -1610C. Explain.
Date posted: March 27, 2019. Answers (1)
- The structure of water molecules can be represented as shown below.(Solved)
The structure of water molecules can be represented as shown below.
Name the bond type represented by letter X and W.
Date posted: March 27, 2019. Answers (1)
- The diagram below shows spots of pure substances A, B and C on a chromatography paper. Spot D is that of a mixture.(Solved)
The diagram below shows spots of pure substances A, B and C on a chromatography paper. Spot D is that of a mixture.
After development, A, B and C were found to have moved 8cm, 3cm and 6cm respectively. D had separated into two spots which had moved 6cm and 8cm.
(i) On the diagram
I. Label baseline
II. Show the positions of all the spots after development.
(ii) Identify the substances present in the mixture D.
Date posted: March 27, 2019. Answers (1)
- Use the information given below to draw the energy cycle diagram for the enthalpy of formation of propane.(Solved)
Use the information given below to draw the energy cycle diagram for the enthalpy of formation of propane.
Date posted: March 27, 2019. Answers (1)
- The PH of a soil sample was found to be 5.7. An agricultural officer recommended addition of lime.
(a) State two functions of the lime.
(b)...(Solved)
The PH of a soil sample was found to be 5.7. An agricultural officer recommended addition of lime. State two functions of the lime.
Date posted: March 27, 2019. Answers (1)
- An element X has a relative atomic mass of 88. When a current of 0.5 ampere was passed through a fused chloride of X for...(Solved)
An element X has a relative atomic mass of 88. When a current of 0.5 ampere was passed through a fused chloride of X for 32 minutes 10 seconds, 0.44g of X was deposited.
(i) Determine the charge of element X [1 Faraday = 96500C]
(ii) Write the formula of hydroxide of X
Date posted: March 27, 2019. Answers (1)
- A form two student in an attempt to prevent rusting put copper and zinc in contact with iron as shown below.(Solved)
A form two student in an attempt to prevent rusting put copper and zinc in contact with iron as shown below.
(i) State what would happen in set up X and Y after one week.
(ii) Explain your answer in diagram Y.
Date posted: March 27, 2019. Answers (1)
- Study the information in the table and answer the questions below.(Solved)
Study the information in the table and answer the questions below.
Describe how a solid sample of substance V could be obtained from a solid mixture of V and W.
Date posted: March 27, 2019. Answers (1)
- Volume of liquids can be measured using a pipette; measuring cylinder or burette. Explain which one would be best for measuring 29.1cm3 of liquid.(Solved)
Volume of liquids can be measured using a pipette; measuring cylinder or burette. Explain which one would be best for measuring 29.1cm3 of liquid.
Date posted: March 27, 2019. Answers (1)
- 0.318g of an oxide of metal M was completely reduced by hydrogen gas to 0.254g of metal. Calculate empirical formula of the metal oxide. (M...(Solved)
0.318g of an oxide of metal M was completely reduced by hydrogen gas to 0.254g of metal. Calculate empirical formula of the metal oxide. (M = 63.5, O = 16)
Date posted: March 27, 2019. Answers (1)
- The volume of a gas at 300C and 780mmHg is 400cm3. What will be its volume at 500C at 600mmHg.(Solved)
The volume of a gas at 300C and 780mmHg is 400cm3. What will be its volume at 500C at 600mmHg.
Date posted: March 27, 2019. Answers (1)
- 15g of sodium chloride was dissolved in 120cm3 of distilled water. Calculate the concentration of the resulting solution in moles per litre. (Na = 23,...(Solved)
15g of sodium chloride was dissolved in 120cm3 of distilled water. Calculate the concentration of the resulting solution in moles per litre. (Na = 23, Cl = 35.5)
Date posted: March 27, 2019. Answers (1)
- The table below gives the rate of decay of a radioactive element G.(Solved)
The table below gives the rate of decay of a radioactive element G.
Calculate the half-life of the radioactive element G.
Date posted: March 27, 2019. Answers (1)
- Study the diagram below and answer the questions that follow.(Solved)
Study the diagram below and answer the questions that follow.
(i) What is the purpose of passing tap water through the air aspirator?
(ii) State and explain the observation that would be made in tube M after sometime.
Date posted: March 27, 2019. Answers (1)
- The diagram below shows a burning jiko. Study it and answer the questions that follow.(Solved)
The diagram below shows a burning jiko. Study it and answer the questions that follow.
(a) Write the equation for the reaction taking place in region A.
(b) Name the gas produced at region B.
(c) State ONE use of the gas named in (b) above.
Date posted: March 27, 2019. Answers (1)
- The table below gives some elements in the periodic table. Use it to answer the questions that follow. The letters do not represent the actual...(Solved)
The table below gives some elements in the periodic table. Use it to answer the questions that follow. The letters do not represent the actual symbols of the elements.
(a) A metallic element which forms ions with the smallest ionic radius? Explain
(b) A non metallic element with the largest atomic size? Explain.
Date posted: March 27, 2019. Answers (1)
- Study the following equilibrium equation.(Solved)
Study the following equilibrium equation.
Suggest two ways of increasing the yield of X2Y.
Date posted: March 27, 2019. Answers (1)
- The curves below represent the volume of carbon (IV) oxide gas evolved once 2M(concentrated) hydrochloric acid was reacted with 100g of powdered calcium carbonate and...(Solved)
The curves below represent the volume of carbon (IV) oxide gas evolved once 2M(concentrated) hydrochloric acid was reacted with 100g of powdered calcium carbonate and also when 1M concentrated hydrochloric acid was reacted with the same quantity of carbonate.
(i) Which of the two curves represents the reaction of 2M concentrated HCl with powdered calcium carbonate. Give a reason.
(ii) Why do the two curves flatten at the same level of production of CO2.
Date posted: March 27, 2019. Answers (1)