x + 4 (-2) = -1
x – 8 =-1
x = 7
Kavungya answered the question on June 22, 2019 at 08:35
- A sealed glass tube containing air at s.t.p was immersed in water at 1000c. Assuming
that there was no increase in the volume of the glass...(Solved)
A sealed glass tube containing air at s.t.p was immersed in water at 1000c. Assuming
that there was no increase in the volume of the glass tube due to the expansion of the
glass, calculate the pressure of the inside tube. (standard pressure = 760mmHg,)
Date posted: June 22, 2019. Answers (1)
- Draw the structural formula of:
(a) Ethanol
(b) Propanoic
(c) Give the name of the organic compound formed when ethanol and propanoic
acid react in the presence of concentrated...(Solved)
Draw the structural formula of:
(a) Ethanol
(b) Propanoic
(c) Give the name of the organic compound formed when ethanol and propanoic
acid react in the presence of concentrated sulphuric acid.
Date posted: June 22, 2019. Answers (1)
- State and explain the observation that would be made if a few pellets of potassium
hydroxide are added to the equilibrium mixture.(Solved)
State and explain the observation that would be made if a few pellets of potassium
hydroxide are added to the equilibrium mixture.
Date posted: June 22, 2019. Answers (1)
- On complete combustion of a sample of hydrocarbon, 3.52 gm of carbon dioxide and
1.44g of water were formed. Determine the molecular formula of the hydrocarbon.
(Relative...(Solved)
On complete combustion of a sample of hydrocarbon, 3.52 gm of carbon dioxide and
1.44g of water were formed. Determine the molecular formula of the hydrocarbon.
(Relative molecular masses of hydrocarbon =56, carbon dioxide 44, water = 18 and
relative atomic masses H = 1.0 and c=12.0)
Date posted: June 22, 2019. Answers (1)
- An isotope of Uranium 234U, decays by emission of an alpha particle to thorium
...(Solved)
An isotope of Uranium 234U, decays by emission of an alpha particle to thorium
92
a) Write the equation for the nuclear reaction undergone by isotope.
b) Explain why it is not safe to store radioactive substances in containers made
from aluminium sheets.
Date posted: June 22, 2019. Answers (1)
- 1.9 g of magnesium chloride was dissolved in distilled water. Silver
nitrate solution was added until in excess. Calculate the mass of silver
nitrate that was used...(Solved)
1.9 g of magnesium chloride was dissolved in distilled water. Silver
nitrate solution was added until in excess. Calculate the mass of silver
nitrate that was used for the complete reaction. Relative molecular mass of
magnesium chloride = 95, N = 14.0, O = 16.0, Ag = 108.0
Date posted: June 22, 2019. Answers (1)
- Chloride can be prepared by using the following three agents; solid
sodium chloride, concentrated sulphuric acid and potassium permanganate
(i) What is the role of each of...(Solved)
Chloride can be prepared by using the following three agents; solid
sodium chloride, concentrated sulphuric acid and potassium permanganate
(i) What is the role of each of the following in the reaction?
I Concentrated sulphuric acid
II potassium permanganate
(ii) Name the bleaching agent formed when chlorine gas is passed through
cold dilute sodium hydroxide solution
(iii) Name one other use of the compound formed in (ii) above other than
bleaching
Date posted: June 22, 2019. Answers (1)
- A factory uses nitric acid and ammonia gas as the only reactants for the
preparation of fertilizer. If the daily production of the fertilizer is 4800...(Solved)
A factory uses nitric acid and ammonia gas as the only reactants for the
preparation of fertilizer. If the daily production of the fertilizer is 4800 kg
calculate the mass of ammonia gas used daily.
Date posted: June 22, 2019. Answers (1)
- Calculate the mass of nitrogen dioxide gas that would occupy the same volume as
10g of hydrogen gas at same temperature and pressure.(H = 1.0, N...(Solved)
Calculate the mass of nitrogen dioxide gas that would occupy the same volume as
10g of hydrogen gas at same temperature and pressure.(H = 1.0, N = 14.0, o =
16.0)
Date posted: June 22, 2019. Answers (1)
- When 0.6g of element J were completely burnt in oxygen and all the heat evolved
was used to heat 500cm3 of water, the temperature of the...(Solved)
When 0.6g of element J were completely burnt in oxygen and all the heat evolved
was used to heat 500cm3 of water, the temperature of the water rose from 23oC to
32OC. Calculate the relative atomic mass of element J given that the specific heat
capacity of water = 4.2JK-1
g-1, density of water = 1.0g/cm3 and molar heat is
combustion of J is 380Kjmol-1
Date posted: June 22, 2019. Answers (1)
- Name and draw the structure of the compound formed when methane reacts with
excess chlorine in the presence of U.V light(Solved)
Name and draw the structure of the compound formed when methane reacts with
excess chlorine in the presence of U.V light
Date posted: June 22, 2019. Answers (1)
- 0.63g of lead powder were dissolved in excess nitric acid to form lead nitrate
solution. All the lead nitrate solution was reacted with sodium sulphate solution.
a)Write...(Solved)
0.63g of lead powder were dissolved in excess nitric acid to form lead nitrate
solution. All the lead nitrate solution was reacted with sodium sulphate solution.
a)Write an ionic equation for the reaction between lead nitrate and sodium
sulphate solutions.
b) Determine the mass of the lead salt formed in (a) above.
(Pb = 207, S = 32.0 = 16)
Date posted: June 22, 2019. Answers (1)
- Potassium sulphite solution was prepared and divided into two portions. The first
portion gave a white precipitate when reacted with barium nitrate. On addition of
dilute hydrochloric...(Solved)
Potassium sulphite solution was prepared and divided into two portions. The first
portion gave a white precipitate when reacted with barium nitrate. On addition of
dilute hydrochloric acid the white precipitate disappeared.
a) Write the formula of the compound which formed as the white precipitate.
b) Write the equation for the reaction between dilute hydrochloric acid and
the compound whose formula is written in (a) above.
c) What observation would be made if one drop of potassium dichromate
solution was added to the second portion followed by dilute hydrochloric
acid?
Date posted: June 22, 2019. Answers (1)
- The empirical formula of a hydrocarbon is C2H3.The hydrocarbon has
a relative molecular mass of 54..(H = 1.0, C = 12.0).
a) C2H3
b) Draw the structural formula...(Solved)
The empirical formula of a hydrocarbon is C2H3.The hydrocarbon has
a relative molecular mass of 54..(H = 1.0, C = 12.0).
a) C2H3
b) Draw the structural formula of the hydrocarbon
c) To which homologous series does the hydrocarbon drawn in (b) above
belong?
Date posted: June 22, 2019. Answers (1)
- Complete the table below by inserting the missing information in the space
provided.
(Solved)
Complete the table below by inserting the missing information in the space
provided.
Date posted: June 22, 2019. Answers (1)
- The graph below shows the solubility of sulphur dioxide gas at different
temperatures. Use the following in it to answer the questions that follow.
From the graph...(Solved)
The graph below shows the solubility of sulphur dioxide gas at different
temperatures. Use the following in it to answer the questions that follow.
From the graph determine:
I The lowest temperature at which 1,000cm3 of solution would contain
116g of sulphur dioxide.
II The maximum mass of sulphur dioxide that would dissolve in 15 litres of
solution at 100C
Date posted: June 22, 2019. Answers (1)
- Sodium thiosulphate solution reacts with dilute hydrochloric acid according to the
following equation.
S2O32- (aq) + 2H+ (aq) ---> H2O (l) + SO2 + S(s)
In an experiment...(Solved)
Sodium thiosulphate solution reacts with dilute hydrochloric acid according to the
following equation.
S2O32- (aq) + 2H+ (aq) ---> H2O (l) + SO2 + S(s)
In an experiment to study how the rate of reaction varies with concentration,
10cm3 of 0.4M sodium thiosulphate was mixed with 10cm3. Of 2M hydrochloric acid in a
flask. The flask was placed in a white paper marked with across X.The time taken for the
cross X become invisible when viewed from above was noted and recorded in the table
below. The experiment was repeated three times as the temperature using the volumes in
the table and the results recorded as shown in the table below.
a) i) On the grid below, plot a graph of the volume of thiosulphate (Vertical
axis) against time taken for the cross (X) to become invisible)
ii) From the graph determine how long it would take for the cross to become
invisible if the experiment was done.
i) Using 6cm3 of the 0.4M thiosulphate
ii) Using 6cm3 of 0.2M thiosulphate solution
b) i) Using values for experiment I.Calculate
i) Moles of thiosulphate used
ii) Moles of hydrochloric acid used
ii) Explain which of the two reactants in experiment I controlled the rate of
the reaction? Explain
c) Give two precautions which should be taken in experiment I controlled the rate of
the reaction? Explain
Date posted: June 22, 2019. Answers (1)
- Complete the diagram below to show how a and b particles from a radioactive source
can be distinguished from each other. Label your diagram clearly(Solved)
Complete the diagram below to show how a and b particles from a radioactive source
can be distinguished from each other. Label your diagram clearly
Date posted: June 22, 2019. Answers (1)
- Explain why it is not advisable to use aqueous chloride solution as the salt bridge in the
electrochemical cell formed between half cells, Pb2-(aq)/pb(s) E0 =...(Solved)
Explain why it is not advisable to use aqueous chloride solution as the salt bridge in the
electrochemical cell formed between half cells, Pb2-(aq)/pb(s) E0 = 0.13V and
CU2 + (aq) + (aq)/CU2+(aq)/Cu2(s) E0=0.34V
Date posted: June 22, 2019. Answers (1)
- Oxygen reacts with the elements phosphorous, sulphur and chlorine to from oxides oxide
of sulphur and its highest oxidation number. Complete the table for phosphorus and
chlorine....(Solved)
Oxygen reacts with the elements phosphorous, sulphur and chlorine to from oxides oxide
of sulphur and its highest oxidation number. Complete the table for phosphorus and
chlorine. (Atomic numbers: P=15, S= 16 Cl = 17)
Date posted: June 22, 2019. Answers (1)