Half life is the time required for a radioactive substance to decay to half its of original mass or amount
32906521 answered the question on September 19, 2017 at 08:52
- Explain how alkaline solution is useful on acidic soil(Solved)
Explain how alkaline solution is useful on acidic soil
Date posted: September 18, 2017. Answers (1)
- Iron is extracted from its ore by the blast furnace process
a) Name chief ore from which iron is extracted from.
b) An ore is suspected to...(Solved)
Iron is extracted from its ore by the blast furnace process
a) Name chief ore from which iron is extracted from.
b) An ore is suspected to contain mainly iron. Describe a method that can be used to confirm the presence of iron in the ore
Date posted: September 18, 2017. Answers (1)
- Explain why hard water flowing in lead pipes may be safer for drinking than soft water
flowing in the same pipes.(Solved)
Explain why hard water flowing in lead pipes may be safer for drinking than soft water
flowing in the same pipes.
Date posted: September 18, 2017. Answers (1)
- In terms of structure and bonding. Explain why water (H2O) is a liquid at room temperature while Hydrogen sulphide (H2S) is a gas.(Solved)
In terms of structure and bonding. Explain why water (H2O) is a liquid at room temperature while Hydrogen sulphide (H2S) is a gas.
Date posted: September 18, 2017. Answers (1)
- In an experiment to determine the solubility in water at 300c, the following results were obtained.
Mass of empty evaporating dish = 26.2g
Mass of evaporating dish...(Solved)
In an experiment to determine the solubility in water at 300c, the following results were obtained.
Mass of empty evaporating dish = 26.2g
Mass of evaporating dish + saturated solution = 42.4g.
Mass of evaporating dish + dry solid Y = 30.4g
Use this data to calculate the solubility of Y at 300C.
Date posted: September 18, 2017. Answers (1)
- Define solubility(Solved)
Define solubility
Date posted: September 18, 2017. Answers (1)
- a) State and explain the observations made when chlorine water is exposed to light after 24 hours. (b)State one use of chlorine gas(Solved)
a) State and explain the observations made when chlorine water is exposed to light after 24 hours.
b)State one use of chlorine gas
Date posted: September 18, 2017. Answers (1)
- Highlight the steps followed when lighting a Bunsen burner(Solved)
Highlight the steps followed when lighting a Bunsen burner
Date posted: September 18, 2017. Answers (1)
- M grammes of a radioactive isotope decayed to 5 grammes in 100 days. The half life of the
isotope is 25 days.
(a) What is meant by...(Solved)
M grammes of a radioactive isotope decayed to 5 grammes in 100 days. The half life of the
isotope is 25 days.
What is meant by half life
Date posted: September 18, 2017. Answers (1)
- A student burnt magnesium ribbon in a gas jar full of sulphur (IV) oxide gas.
(i) State two observations made in the gas jar
(ii) Write an...(Solved)
A student burnt magnesium ribbon in a gas jar full of sulphur (IV) oxide gas.
(i) State two observations made in the gas jar
(ii) Write an equation for the reaction that took place
Date posted: September 18, 2017. Answers (1)
- A student fetched water from a river in a limestone area. He used it for washing and
realized that it did not lather easily.
(i) Name the...(Solved)
A student fetched water from a river in a limestone area. He used it for washing and
realized that it did not lather easily.
(i) Name the two ions that prevent lathering
ii)Given that the structure of soap is C17H35COONa.Explain by means of ionic equations how the above ions prevent lathering
Date posted: September 18, 2017. Answers (1)
- 5.0g of calcium carbonate were allowed to react with 25cm3 of 1.0M hydrochloric acid until there was no further reaction. Calculate the mass of calcium...(Solved)
5.0g of calcium carbonate were allowed to react with 25cm3 of 1.0M hydrochloric acid until
there was no further reaction. Calculate the mass of calcium carbonate that remained
unreacted(Ca = 40, C = 12, O = 16).
Date posted: September 18, 2017. Answers (1)
- Study the following equilibrium equation
2X2(g) + Y2(g)<------> 2X2Y(g) H = -197kJ/mol
Suggest two ways of increasing the yield of X2Y(Solved)
Study the following equilibrium equation
2X2(g) + Y2(g)<------> 2X2Y(g) H = -197kJ/mol
Suggest two ways of increasing the yield of X2Y
Date posted: September 18, 2017. Answers (1)
- Give two physical properties of hydrogen gas(Solved)
Give two physical properties of hydrogen gas
Date posted: September 18, 2017. Answers (1)
- (a) Proteins are obtained from amino acids monomers. Complete the equation below to show the polymer formed.
H2NCH2COOH + H2NCHCH3COOH ---------->H2O +---------
b)Name the type of polymerization...(Solved)
(a) Proteins are obtained from amino acids monomers. Complete the equation below to show the polymer formed.
H2NCH2COOH + H2NCHCH3COOH ---------->H2O +---------
b)Name the type of polymerization shown above
Date posted: September 18, 2017. Answers (1)
- Dry carbon (II) oxide gas was passed over heated lead (II) oxide.
(a) Write an equation for the reaction
(b) Give one industrial application of the above...(Solved)
Dry carbon (II) oxide gas was passed over heated lead (II) oxide.
(a) Write an equation for the reaction
(b) Give one industrial application of the above reaction.
(c) Name another gas that can be used in the above reaction.
Date posted: September 18, 2017. Answers (1)
- Explain the effects of the accumulation of nitrogenous compounds in water masses?(Solved)
Explain the effects of the accumulation of nitrogenous compounds in water masses?
Date posted: September 18, 2017. Answers (1)
- State two conditions that would make the boiling point of water to be higher than 100oC(Solved)
State two conditions that would make the boiling point of water to be higher than 100oC
Date posted: September 18, 2017. Answers (1)
- a)Why is the percentage of carbon(IV)oxide in the atmosphere fairly constant? (b)Calculate the volume of carbon(IV)oxide in 8,000 m3 of air contained in a hall.(Solved)
a)Why is the percentage of carbon(IV)oxide in the atmosphere fairly constant?
b)Calculate the volume of carbon(IV)oxide in 8,000 m3 of air contained in a
Date posted: September 18, 2017. Answers (1)
- Which two elements will react more vigorously with each other between fluorine, neon, sodium, magnesium?(Solved)
Which two elements will react more vigorously with each other between fluorine, neon, sodium, magnesium?
Date posted: September 17, 2017. Answers (1)