-Boiling and melting points of alkali metals decreases down the group due to increase in
atomic radius thus reducing the nuclear force of attraction
- melting and boiling points of halogens increase due to increase in the molecular size that
requires more energy to break.
sharon kalunda answered the question on May 16, 2019 at 12:48
- Helium is used instead of Hydrogen to fill balloons.Explain(Solved)
Helium is used instead of Hydrogen to fill balloons.Explain
Date posted: May 16, 2019. Answers (1)
- A solution containing 0.1m sulphuric acid has a pH of 2 while 5M has a pH of more than two.
Explain.(Solved)
A solution containing 0.1m sulphuric acid has a pH of 2 while 5M has a pH of more than two.
Explain.
Date posted: May 16, 2019. Answers (1)
- When a current of 2.5 amperes was passed through a cell containing N2+ ions of a metal for 25 minutes, the mass of the cathode increased by...(Solved)
When a current of 2.5 amperes was passed through a cell containing N2+ ions of a metal for
25 minutes, the mass of the cathode increased by 0.36g. ( 1 faraday = 96500 coulombs).Determine the relative atomic mass of element N.
Date posted: May 16, 2019. Answers (1)
- State and explain the observation made in the set-up below.(Solved)
State and explain the observation made in the set-up below.
Date posted: May 16, 2019. Answers (1)
- Explain why aluminium articles are not easily corroded.(Solved)
Explain why aluminium articles are not easily corroded.
Date posted: May 16, 2019. Answers (1)
- A mixture of carbon (IV) Oxide and carbon (II) oxide is passed through potassium hydroxide
solution as shown in the following set up.(Solved)
A mixture of carbon (IV) Oxide and carbon (II) oxide is passed through potassium hydroxide
solution as shown in the following set up.
I) Name gas X
(ii) Why should gas X be burned.
(iii) Write a well balanced chemical equation for the reaction that takes place in the conical
flask in the first few seconds.
Date posted: May 16, 2019. Answers (1)
- Write ionic equations for electrolysis of dilute sulphuric acid using platinum electrodes at:(Solved)
Write ionic equations for electrolysis of dilute sulphuric acid using platinum electrodes at:
(i) Anode
(ii) Cathode
Date posted: May 16, 2019. Answers (1)
- Dilute hydrochloric acid is warmed with sodium sulphide.State a chemical test for the gas evolved.(Solved)
Dilute hydrochloric acid is warmed with sodium sulphide.State a chemical test for the gas evolved.
Date posted: May 16, 2019. Answers (1)
- 100cm3 of 2M Nitric acid reacted with 12.5g of a carbonate MCO3 of metal M, calculate the relative atomic mass of M ( C =...(Solved)
100cm3 of 2M Nitric acid reacted with 12.5g of a carbonate MCO3 of metal M, calculate the relative atomic mass of M ( C = 12, O = 16)
Date posted: May 16, 2019. Answers (1)
- A white solid K was heated. It produced a brown gas A and another gas B which relights a
glowing splint. The residue left was yellow...(Solved)
A white solid K was heated. It produced a brown gas A and another gas B which relights a
glowing splint. The residue left was yellow even after cooling.
a) Identify gases A and B
b) Write a balanced chemical equation for the decomposition of solid K.
Date posted: May 16, 2019. Answers (1)
- Below is a set up used to collect hydrogen gas.(Solved)
Below is a set up used to collect hydrogen gas.
a) Identify with reasons, two mistakes in the set up.
b) Explain the role of hydrogen in the manufacture of margarine.
Date posted: May 16, 2019. Answers (1)
- Complete the following reactions.(Solved)
Complete the following reactions.
Date posted: May 16, 2019. Answers (1)
- The scheme below shows some reaction sequence starting with solid M(Solved)
The scheme below shows some reaction sequence starting with solid M
(i) Name Solid M
(ii) Write the formula of complex ion present in Solution Q
(iii) Write ionic equation of reaction between barium nitrate and solution N.
Date posted: May 16, 2019. Answers (1)
- What is the oxidation number of chlorine in ClO-4?(Solved)
What is the oxidation number of chlorine in ClO-4?
Date posted: May 16, 2019. Answers (1)
- Identify the acid and base in the equation below.(Solved)
Identify the acid and base in the equation below.
Date posted: May 16, 2019. Answers (1)
- In terms of structure and bonding explain why diamond has a high melting point while
graphite has a low melting point.(Solved)
In terms of structure and bonding explain why diamond has a high melting point while
graphite has a low melting point.
Date posted: May 16, 2019. Answers (1)
- A compound G reacts with 2 moles of bromine to form another compound whose graphical
formula is.(Solved)
A compound G reacts with 2 moles of bromine to form another compound whose graphical
formula is.
i) What is the formula and name of compound G
ii) State the observations made when acidified potassium chromate (VI) is
added to compoundG
Date posted: May 16, 2019. Answers (1)
- Explain why the compound Cl2O has a very low melting and boiling point.(Solved)
Explain why the compound Cl2O has a very low melting and boiling point.
Date posted: May 16, 2019. Answers (1)
- Two elements A and B have electronic configurations 2.8.3 and 2.6 respectively.(Solved)
Two elements A and B have electronic configurations 2.8.3 and 2.6 respectively.
a) To which group and period does element B belong?
b) If the two react, what is the formula of the compound they form
Date posted: May 16, 2019. Answers (1)
- The graph below shows the decay for a sample of 400g of iodine -131. Study is and
answer question that follow.(Solved)
The graph below shows the decay for a sample of 400g of iodine -131. Study is and
answer question that follow.
(i) Use the graph to determine the half-life of the sample
(ii) What fraction of the original sample remains after 16.2 days.
Date posted: May 16, 2019. Answers (1)