- 233 Pa decays by beta emission. What is the mass number and
91
Atomic number of the element formed?(Solved)
233 Pa decays by beta emission. What is the mass number and
91
Atomic number of the element formed?
Date posted: June 22, 2019. Answers (1)
- 100gm of radioactive 233 Pa was reduced to 12.5g after 81 days.
...(Solved)
100gm of radioactive 233 Pa was reduced to 12.5g after 81 days.
91
Determine the half-life of Pa.
Date posted: June 22, 2019. Answers (1)
- A compound C4H10O_ is oxidized by excess acidified potassium permanganate to..(Solved)
A compound C4H10O_ is oxidized by excess acidified potassium permanganate to
form another compound C4H8O2. The same compound C4H10O reacts with
potassium to produce hydrogen gas.
a) Draw the structural formula and name the compound CaH10O
b) Write an equation for the reaction between potassium and compound
C4H10O.
Date posted: June 22, 2019. Answers (1)
- A compound has an empirical formula, C3H6O and a relative formula mass of 116.
Determine its molecular formula (H + 1.0, C = 12.0, O =...(Solved)
A compound has an empirical formula, C3H6O and a relative formula mass of 116.
Determine its molecular formula (H + 1.0, C = 12.0, O = 165.0)
Date posted: June 22, 2019. Answers (1)
- Duralumin is an alloy of aluminium. What is the advantage of using duralumin
in place of aluminium for manufacture of aeroplane parts.(Solved)
Duralumin is an alloy of aluminium. What is the advantage of using duralumin
in place of aluminium for manufacture of aeroplane parts.
Date posted: June 22, 2019. Answers (1)
- In an experiment, rods of metals P, Q and R were cleaned with sand paper and
placed in a beaker containing water. Another set of rods...(Solved)
In an experiment, rods of metals P, Q and R were cleaned with sand paper and
placed in a beaker containing water. Another set of rods was also cleaned and
placed in a beaker containing dilute acid. After placing the rods in the two liquids
bubbles of gas were seen around some of the rods as shown in the diagrams
below.
a) Why is it necessary to clean the rods with sand paper before dipping them
into the liquids.
b) Arrange the three metals in order of their reactivity starting with the most
reactive.
Date posted: June 22, 2019. Answers (1)
- Give one advantage of synthetic fibres over natural fibres.(Solved)
Give one advantage of synthetic fibres over natural fibres.
Date posted: June 22, 2019. Answers (1)
- Calculate the amount of calcium carbonate that would remain if 15.0g of calcium
carbonate were reacted with 0.2 moles of hydrochloric acid.
The equation for the reaction...(Solved)
Calculate the amount of calcium carbonate that would remain if 15.0g of calcium
carbonate were reacted with 0.2 moles of hydrochloric acid.
The equation for the reaction is CaCO3 (g) + 2HCl CaCl2 (aq) + CO2 (g) + H2O (g)
(C = 12.0 = 1.60, Ca = 40.0)
Date posted: June 22, 2019. Answers (1)
- 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. Answers (1)
- 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. Answers (1)
- 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. Answers (1)
- What is the native name of sodium?(Solved)
What is the native name of sodium?
Date posted: June 9, 2019. Answers (1)
- 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. Answers (1)
- 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. Answers (1)
- What is a dimer?(Solved)
What is a dimer?
Date posted: June 4, 2019. Answers (1)
- 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)