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A mass of M grams of radioactive isotopes decay to 5 grams in 100 days. The half-life of the isotope is 25 days. What is the initial...
(Solved)
A mass of M grams of radioactive isotopes decay to 5 grams in 100 days. The half-life of the isotope is 25 days. What is the initial mass of the isotope?
Date posted:
June 13, 2019
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Answers (1)
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Define analytical chemistry and outline areas in which analytical chemistry is involved?
(Solved)
Define analytical chemistry and outline areas in which analytical chemistry is involved?
Date posted:
June 12, 2019
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Answers (1)
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How do you recognize oxidizing and reducing agents in a chemical reaction using oxidation states?
(Solved)
How do you recognize oxidizing and reducing agents in a chemical reaction using oxidation states?
Date posted:
June 11, 2019
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Answers (1)
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What is the native name of sodium?
(Solved)
What is the native name of sodium?
Date posted:
June 9, 2019
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Answers (1)
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You are provided with the following reagents; dilute nitric acid, dilute sulphuric acid, and lead (II) oxide. Describe clearly how you would prepare a sample...
(Solved)
You are provided with the following reagents; dilute nitric acid, dilute sulphuric acid, and lead (II) oxide.
Describe clearly how you would prepare a sample of lead (II) sulphate.
Date posted:
June 6, 2019
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Answers (1)
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Given a mixture of sodium chloride crystals,ammonium chloride and lead(ii)chloride, describe how you would separate all the four solids using methyl benzene,a source of heat and...
(Solved)
Given a mixture of sodium chloride crystals,ammonium chloride and lead(ii)chloride, describe how you would separate all the four solids using methyl benzene,a source of heat and water.
Date posted:
June 6, 2019
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Answers (1)
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What is a dimer?
(Solved)
What is a dimer?
Date posted:
June 4, 2019
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)
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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
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Answers (1)