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A dimer is a replicative unit in which two
separate plasmids have been joined, and a
tetramer is a single unit consisting of four
monomers fused together.
Felix Kipkirui answered the question on June 10, 2019 at 20:14
- Why is potassium nitrate preferred in the laboratory preparation of nitric(V) acid?(Solved)
Why is potassium nitrate preferred in the laboratory preparation of nitric(V) acid?
Date posted: June 4, 2019. Answers (1)
- How does heat combustion of paraffin wax compare to heat combustion of propane?(Solved)
How does heat combustion of paraffin wax compare to heat combustion of propane?
Date posted: May 25, 2019. Answers (1)
- Give the contrasting difference in chemical properties of chlorine and hydrogen?(Solved)
Give the contrasting difference in chemical properties of chlorine and hydrogen?
Date posted: May 24, 2019. Answers (1)
- The grid below shows part of the periodic table. Study it and answer the questions that follows.
a) Give the name of the elements represented by...(Solved)
The grid below shows part of the periodic table. Study it and answer the questions that follows.
a) Give the name of the elements represented by the shaded region.
b) Identify an element which form ion with +2 charge.
c) Which non-metal is most reactive ?
d) Element V is in the second period and group V of the periodic table. Place it on the above grid of the periodic table.
e) State and explain how the atomic radius of U and J compare.
f) Write a chemical equation for the reaction between the oxide of A and water.
g) Explain how the electrical conductivity of A and Y compare.
Date posted: May 24, 2019. Answers (1)
- Study the information given in the table below and answer the questions below.
Calculate the enthalpy change for the reaction.
CH4(g) + Cl2(g) ---> CH3Cl(g) +...(Solved)
Study the information given in the table below and answer the questions below.
Calculate the enthalpy change for the reaction.
CH4(g) + Cl2(g) ---> CH3Cl(g) + HCl(g)
Date posted: May 24, 2019. Answers (1)
- Below is a simple representation of a soap molecule
(Solved)
Below is a simple representation of a soap molecule
Using the structure above show how soap removes an oily smear from the fabric shown below.
Date posted: May 24, 2019. Answers (1)
- A volume of 15cm3 of ethane gas was exploded with 50cm3 of oxygen. If both volumes were measured at the same temperature and pressure, calculate...(Solved)
A volume of 15cm3 of ethane gas was exploded with 50cm3 of oxygen. If both volumes were measured at the same temperature and pressure, calculate the volume of resulting gaseous mixture.
Date posted: May 24, 2019. Answers (1)
- Bottle of sodium carbonate, sodium chloride and sugar have lost their labels. A student prepares and tests an aqueous solution of a sample of each...(Solved)
Bottle of sodium carbonate, sodium chloride and sugar have lost their labels. A student prepares and tests an aqueous solution of a sample of each bottle. The results obtained are as shown below.
Complete the table by filling the correct label for each bottle.
Date posted: May 24, 2019. Answers (1)
- Study the scheme below and answer the questions that follow.
a) Draw the structure of polymer P.
b) Identify compound S.
c) Give the reagents and...(Solved)
Study the scheme below and answer the questions that follow.
a) Draw the structure of polymer P.
b) Identify compound S.
c) Give the reagents and conditions for step I and II
Step I:
Reagent
Condition
Step II:
Reagent
Condition
Date posted: May 24, 2019. Answers (1)
- An element Q has a relative atomic mass of 88. When a current of 0.5A was passed through the fused chloride of Q for 32
minutes...(Solved)
An element Q has a relative atomic mass of 88. When a current of 0.5A was passed through the fused chloride of Q for 32 minutes and 10 seconds, 0.44g of Q were deposited at cathode. Determine the charge on the ion of Q. (1 Faraday = 9650
Date posted: May 24, 2019. Answers (1)
- The electronic structures for elements represented by letters A, B, C and D are
A - 2.8.6 B - 2.8.2 C - 2.8.1 D - 2.8.8
a)...(Solved)
The electronic structures for elements represented by letters A, B, C and D are
A - 2.8.6 B - 2.8.2 C - 2.8.1 D - 2.8.8
a) Select the element which forms :
i) a double charged cation
ii) a soluble carbonate
b) Which element has the shortest atomic radius ?
Date posted: May 24, 2019. Answers (1)
- Some water samples A, B and C were tested with soap solution. The lathering produced was recorded as good or poor. The results are in...(Solved)
Some water samples A, B and C were tested with soap solution. The lathering produced was recorded as good or poor. The results are in the table below.
a) Identify the anions present in sample of water A.
b) Give an advantage of hard water.
c) State one structural difference between a soapy and soapless detergent.
Date posted: May 24, 2019. Answers (1)
- Sequential removal of electrons was done in Y and energy required measured as follows.
a) In which group is element Y. Explain.
b) Element Z is...(Solved)
Sequential removal of electrons was done in Y and energy required measured as follows.
a) In which group is element Y. Explain.
b) Element Z is next to Y and to its left in the same period. Which one between Z and Y has a bigger 1st ionisation energy.
Explain.
Date posted: May 24, 2019. Answers (1)
- Metal S removes oxygen combined with P. Q reacts with an oxide of R and not with an oxide of P. P reacts with cold...(Solved)
Metal S removes oxygen combined with P. Q reacts with an oxide of R and not with an oxide of P. P reacts with cold water
but Q does not.
a) Which is the most reactive metal ?
b) Which is the least reactive metal ?
c) Arrange the metals in order of reactivity starting with most reactive to the least reactive.
Date posted: May 24, 2019. Answers (1)
- Below are PH values of some solutions.
i) Which solution is likely to be
I. acidic rain
II. Potassium hydroxide
ii) A basic substance V...(Solved)
Below are PH values of some solutions.
i) Which solution is likely to be
I. acidic rain
II. Potassium hydroxide
ii) A basic substance V reacted with both solutions Y and X. What is the nature of V.
iii) Identify two substances that show these characteristics in question (ii) above.
Date posted: May 24, 2019. Answers (1)
- Study the sequence of reactions below and answer the questions that follow.
a) Name the process in step 4.
b) What reactant is used to achieve...(Solved)
Study the sequence of reactions below and answer the questions that follow.
a) Name the process in step 4.
b) What reactant is used to achieve step 4 ?
Date posted: May 24, 2019. Answers (1)
- The chief ore of aluminium is bauxite which mainly contains Al2O3.2H2O. The ore is initially purified before aluminium is extracted electrolytically.
a) Identify the main impurity...(Solved)
The chief ore of aluminium is bauxite which mainly contains Al2O3.2H2O. The ore is initially purified before aluminium is extracted electrolytically.
a) Identify the main impurity associated with this ore.
b) Sodium hydroxide solution is used in the purification process. State its role.
Date posted: May 24, 2019. Answers (1)
- The diagram below is a section of a model of the structure of element T.
a) State the type of bonding that exist in T.
b) In...(Solved)
The diagram below is a section of a model of the structure of element T.
a) State the type of bonding that exist in T.
b) In which group of the periodic table does element T belong ? Give a reason.
Date posted: May 24, 2019. Answers (1)
- 20cm3 of an unknown gas Q takes 12.6 seconds to pass through small orifice. 10cm3 of oxygen gas takes 11.2 seconds to diffuse through the...(Solved)
20cm3 of an unknown gas Q takes 12.6 seconds to pass through small orifice. 10cm3 of oxygen gas takes 11.2 seconds to
diffuse through the same orifice under the same conditions of temperature and pressure. Calculate the molecular mass of
unknown gas. (O = 16)
Date posted: May 24, 2019. Answers (1)
- An organic compound with the formula C4H10O reacts with sodium metal to give hydrogen gas and a white solid.
a) Give the formula of the white...(Solved)
An organic compound with the formula C4H10O reacts with sodium metal to give hydrogen gas and a white solid.
a) Give the formula of the white solid.
b) To which homologous series does the organic compound belong.
Date posted: May 24, 2019. Answers (1)